The "Brightest" Near-Infrared Photoluminescent Dyes for Labeling Almost Any Large Biological Molecules or Carriers

Our New Photoluminescent Halo Dyes are the highest brightness non-dark-toxic near-IR dyes in the market. These dyes function in water and on a wide range of carrier molecules, monoclonal antibodies, peptides or nanoparticles. Halo dyes offer multifunctional capabilities never before available. Selected optical characteristics of ICy-105, BrCy106, and BrCy-107-10Proline (with 10 spiral-chain proline linker to reduce aggregation), and the comparable high-performance commercial dye Cy7 are available. Our ICY dyes offer dual X-ray contrast and IR fluorescence.

Several of these new dyes are in stock. These dyes are available with COOH acid terminations of NHS ester terminations. Other linker terminations can be custom produced.

NQS has patents pending on this class of dye. Various derivatives of these dyes are useful as photoluminescent reporters, as photosensitizers.

Derivative dyes have been made with absorption peaks in the red and in the near-IR spectral range. Some derivatives of these dyes also provide other unique capabilities such as high X-ray contrast and other useful characteristics.

NOTE: We recently began discussing partnerships and/or licensing of these new materials. These discussions are being pursued prior to offering of these new dyes for general sale.

Additional information and sample dyes can be made available. Contact us for specific details if there is interest in joint project proposals, joint projects, or in considering a licensing arrangement.

A recent ACS publication in 2017 characterizing BrCy 106 showed high brightness, stability, non-toxicity, and ease of use in visualizing cancers using a targeting carrier: See other recent publications using Halo class photosensitizers and reporters under our Publications tab.

Optical Characteristics and Tumor Imaging Capabilities of Near Infrared Dyes in Free and Nano-Encapsulated Formulations Comprised of Viral Capsids

Yadir Guerrero, Sheela P. Singh, Turong Mai, Ravoori K. Murali, Leela Tanikella, Atta Zahedi, Vikas Kundra, and Bahman Anvari
ACS Applied Materials & Interfaces 2017 9 (23), 19601-19611
DOI: 10.1021/acsami.7b03373

These new high quantum efficiency, high sensitivity photoluminescent dyes (fluorescent labels or probes) can enable many new analytical, diagnostic, and surgical imaging aid opportunities for:

  • Increased spectral range and improved sensitivity for cytometry and other analytical methods. These dyes exhibit differentiable decay characteristics relative to other dyes in the market

  • High brightness, near-infrared fluorescent research and diagnostic agents with high photostability and high chemical stability relative to most other near-IR fluorescent label dyes

  • Multifunctional X-ray contrast agents with high brightness near-infrared imaging labeling capabilities

  • Enhanced in vivo monitoring of the movement of drugs and other materials in the body for research, drug development, diagnosis, and real-time control of therapies

  • Aids to label and identify selected tissues or body fluids over a greater range of depths than previously available non-toxic near-IR labeling dyes: Applications include identification and labeling of targeted vs. non-targeted tissues for surgery, radiation treatments, and other therapies. These include any tissues a targeting mechanism exists for including cancers, lipomas, infected regions, lipid deposits, and other biological materials where selective targeting agents are available that can aid conventional surgery or radiological surgical methods can be enhanced using these techniques.

  • Potential for use as near-IR absorption photoacoustic agents with near-IR fluorescence capability

  • Some of these new dyes also can exhibit X-ray contrast as high as the best non-ionic contrast agents, while retailing their potential dual use as NIR fluorescent dyes. This unique dual functionality could enable precision location of concentrations of MAb or other dye carriers anywhere in the body using an X-Ray imaging, and then real-time monitoring of target movement or close-up locating targeted tumors or infections.

Near-IR Photosensitizers for Targeted Photodynamic Therapy Deeper in Tissue than Other Photosensitizers

These new ICy Halo photosensitizers have shown the potential to be more effective at many times greater depths in tissue than any other not-dark-toxic photosensitizers in the near-IR range that can be easily attached to almost any type of targeting carrier. Our photosensitizers convert a higher percentage of the absorbed light energy into manufacturing Reactive Oxygen Species (ROS) than into light, relative to our brightest fluorescent labels. Our photosensitizers are still all fluorescent in the near-IR, making tracking these photosensitizers and determining their status relatively easy.

Our high efficiency, ultra-high sensitivity photosensitizers should enable many new analytical, diagnostic, and therapeutic opportunities such as the following:

  • Selectively attaching to cell with a high affinity for targeting carriers and then killing almost any cell or pathogen type only where the near-infra red light is provided, with minimal anticipated damage to non-targeted cells.

  • Never before available depth of light activation due to high sensitivity, ROS generation, high-stability, and high selective photosensitizer concentration at the targeted cells or pathogens.

    Recent studies have shown that bacteria and cancer cells exposed to ROS have not developed immunity after many hundreds of thousands of generations.

  • Because these photosensitizers create the cancer cell killing ROS from oxygen using externally applied light energy, each photosensitizer molecule can create a large number of toxic molecules, amplifying the drug’s potential effectiveness at lower cost and reducing the risk of side effects from the drug when the special near-IR spectrum light is not present. Also, these cancer and pathogen killing ROS toxins deactivate so quickly that they typically cannot kill a cell unless they are inside the cell or directly on the surface of an active bacterium or virus.

  • Because these new photosensitizers and fluorescent labels are not toxic without near-infra red activating light and are minimally sensitive to photons in most of the visible light spectral range, they should result in lower risk of side effects in the liver and kidneys than typical toxic chemotherapy drugs and conventional antimicrobials drugs at the concentrations needed for high effectiveness.

    Our research has indicated that conjugates of multiple dye molecules around a core ROS generator may be a way to further increase photosensitizer effectiveness at even lower dosages and greater activation depth ranges. A few test interesting dye conjugates have been synthesized, but limited resources prevented further exploration of this path.

    Potential applications include oncology, antibacterial, antiviral, and more.

    The most recent published 2017 study using one of the ICy dyes showed effectiveness pancreatic cancer in small animals.


Nanoquantum can also assist with the design and manufacturing of custom flexible, cooled, large area light sources for near-IR diagnostics, in vivo imaging, PDT activation, and analytical uses


While considerably more development and characterization would be required before clinical trials, the new molecules and techniques being explored by Nanoquantum Sciences may someday be highly effective on solid tumors and possibly also on distributed cancer cells when coupled with the right selective targeting agents such as peptides or MAb. These techniques being investigated may also be adaptable to permit selective-toxicity to isolated cancer cells and other pathogens anywhere the patient’s tissue is exposed to a sufficient dose of activating near-IR light, with reduced risk of damage to neighboring cells or other organs and a lower probability of side effects than most alternative treatments. Because of the deep penetration of near-IR light and the ultra-high sensitivity of these materials, greater volume photodynamic therapy over large segments of the body and in the blood may become possible.

Activity is restricted to where the light is provided, providing both zoned and individual cell selectivity. Like many other sensitizers, each sensitizer dye molecue can produce many ROS molecules using oxygen in the body to initiate highly localized cell apoptosis.

Allowing general clearing from a targeted area before NIR light exposure could permit only the cells with an affinity to the chosen targeting carrier(s) to be effected without danage to surrounding tissue, even for treatments in tissue such as the liver or kidneys that scavenge and concentrate most drugs. Also, combinations of selective carriers could address cancer mutations and allow effective followup treatments since cells do not develop an immunity to the ROS produced by these dyes. A great many Mab have been identified around the world with affinity for almost every class of cancer cell, even though many of the Mab and peptides have no direct therapeutic value. This can permit many selective carriers to be to taget a near infinite number of mutations, including bacteriophage carriers. Considerable work would be required to properly characterize this methodology, but a high extinction, low dark-toxicity photosensitizer that is activated in the spectral range where blood has the lowest absoption could be the key to unlocking a new treatment methodology.

Thousands of MAb and other targeting carriers with minimal direct therepeutic benefit can become far more valuable.

  • Near-infrared light from LEDs or other light sources in the 720nm-760nm spectral range provides the energy for activating photodynamic therapy (PDT) conjugates made using these new photosensitizers.

Near-infrared (Near-IR or NIR) wavelength range light is safe and occurs naturally in sunlight. Near-IR light is also present in most man made white-light sources other than cool-white and other deep-red-deficient LEDs used in general lighting. Low-cost, high-power LEDs and lasers are available in this wavelength range. Use of the near-infrared light spectrum permits the deepest tissue penetration of any non-ionizing radiation and can easily penetrate through bone. Near-infrared light can be used at much higher intensities than other visible or infrared wavelengths without heat discomfort because the light energy is absorbed over a greater depth & volume of tissue, further increasing the practical penetration-activation depth range. Light source-to-target tumor distances over 4-8 centimeters (about 1.5-4.0 inches) from the light source appear possible for many parts of the body depending on dye concentration at the target, intensity, and duration of exposure.

This is due to the ultra-high, near-IR sensitivity of these new photosensitizers coupled with the photosensitizer concentration effects provided by many selective carriers loading on most targeted cells. 720-760nm light used for activation of the dyes easily passes through all skin types reasonably well, so ethnicity should minimally influence the effectiveness of this methodology.

Several times higher intensity light can be used in this near-IR spectral range causing heat discomfort than the rest of the visible light or infrared spectral ranges. Because the body’s tissue is highly translucent to these wavelengths, energy is distributed over a much greater volume of tissue than in conventional (under 700nm excitation) photodynamic therapy (PDT). Higher intensity coupled with higher transmission provides depth of potential effectiveness from the light source.

When the near-infrared spectrum activating light is paired with 1) high selectivity drug carriers that concentrate the drugs on the targeted cells, 2) PDT materials exhibiting very high extinction coefficients to efficiently absorb light, and 3) high quantum efficiencies at producing ROS to chemically act on the targeted materials, minimally-invasive and non-invasive surgical techniques should become viable for treating cancers and pathogens deep in the body that today pose high tissue damage risk and patient survival risk.

Furthermore, many published studies have shown that ROS generating photosensitizers can enhance the body's ability to recognize cancer cells, potentially providing an increased probability of a second broader attack by the body's immune system on the cancer following treatment.

Treatments of cancer and other pathogens could potentially be minimally invasive, almost immediate in tumor or pathogen deactivation, and short in treatment duration with minimal side effects relative to conventional therapies using toxic compounds.Illustration 1: Conceptual drawing of PSCN ds.

Illustration 1: Conceptual drawing of an example photosensitizer and carrier conjugate using a bacteriophage as the carrier. Monoclonal antibodies, proteins, peptides, nanoparticles, and other targeting carriers also work in a similar manner. Some carriers such as some types of MAb can also accelerate uptake of the photosensitizer by the targeted cancer cells or pathogens prior to near-IR light exposure, increasing the photosensitizer's effective potency.

In this conceptual diagram we show a bacteriophage with photodynamic compound conjugates and fluorescent reporters attached to the phages coat. Most of the binding sites on the phage are not used by the attached compounds, leaving these sites available to provide affinity binding to the targeted cells or pathogens.

Filamentous bacteriophages (phage) or other cancer-cell targeting carriers can act as carriers for photodynamic materials. Human-tumor-specific or target pathogen-specific peptides genetically fused to the approximately large numbers of a phages’ major pVIII coat proteins can be selected from multi-billion phage clone libraries by their ability to bind to specific cancer cells or pathogen surfaces.

When billions of phage variants are applied to cancer cells obtained from a biopsy or to samples of a pathogen, those few phage with an affinity to the target cells or pathogens are retained. The other phages are then rinsed away. The retained phages are feed bacteria and rapidly increase in quantity. This selection process is repeated several times until many phages with a high affinity to the target cell types remain. A variation of this process can be used to verify the selected phage have low affinity to normal cells.

Other carriers such as monoclonal antibodies or peptides with a high affinity for a particular type of cancer call can also be used as targeting carriers. These carriers can provide the added advantage of higher cell uptake and may require smaller amounts of photosensitizer to be effective.


About Bacteriophages (Phages)

Phages are almost always present in the human intestinal tract, feeding on bacteria such as E. coli.

Over one hundred types of phages are typically present in an average person’s intestines, and to a lesser degree are present in other parts of the body. Phages frequently go unnoticed since they minimally interact with human or animal cells. While the selected phage being researched for this treatment do attach to cell membranes, the phage themselves are not expected to directly interfere with even the targeted cells. Phage can feed on some bacterial pathogens, but the proposed therapy does not rely on lytic interactions between bacteria and phage.

Filamentous phages have been shown to pass through almost all of the body’s multi-cellular boundaries and most biofilms, but they do not penetrate individual human cell membranes. While phages are continually entering the body through the intestines, they are quickly removed in a similar manner as particles from the blood stream by the liver so their concentration is typically low in the blood. Phages are therefore typically only present in small quantities in various tissues including blood, lymph system, and brain.

Because the specific phage carrier that best targets a specific person's cancer (or mixture of cancer mutations) may be a small number of strains from a multibillion phage variant collective, specific government approval to utilize such a method appears unlikely since each drug would be very unique to each patient, even though the phage characteristics other than target affinity would be similar. Utilizing a heterogeneous targeting methodology to treat heterogeneous afflictions such as cancer or mutation-prone pathogens seems elegant, but there we know of no mechanism for obtaining approval of such a highly-personalized drug at this time in the USA.

Therefore, we are focusing our current development efforts on utilizing specific well-understood targeting carriers such as certain MAb and peptides. In this case, a specific carrier and specific photosensitizer can be tested and potentially approved for use treating a specific type targeted cancer cell. Since there are common affinity characteristics for some subsets of certain types of cancers and pathogens, these targets are our best path to creating something that may be proven safe and effective and someday made available to patients.


About Monoclonal Antibodies (MAb), Peptides, and other Selective Drug Carriers

Other selective drug carriers such as monoclonal antibodies (MAb), peptides, and nanoparticles that exhibit a high affinity for a particular type of cancer cell or other pathogen can also be used as targeting carriers.

Many of these materials have been developed by other organization to directly treat cancers utilizing specific cell pathways. Materials that as highly selective carriers to specific targets now may be useful, even though those carriers may not have therapeutic value on their own.

Many different targeting carriers have been used with many different chemotherapy drugs in many studies around the world to improve chemotherapy effectiveness and reduce side effects; however carriers and their payload of chemotherapy drugs will still accumulate in the liver and kidneys that filter the blood. Other organs may also accumulate the drugs or carriers in addition to the targeted tumors or pathogen sites. Liver and kidney toxicity issues still limit the dosages of conventional toxic chemotherapy drugs, and therefore limit the effectiveness of this technique. Since the new photosensitizers in development appear non-toxic at even relatively high dosages unless near-IR light is provided, this toxicity issue may be finally circumvented. Verification of non-toxicity across a far larger range of cell types and in vivo are still required, but our initial in vitro results have been encouraging.

Drug carriers can provide the added advantage of higher cell uptake and therefore may require smaller quantities of photosensitizer for effectiveness.

The disadvantage of most carriers for photosensitizers is that a great many types must be independently developed and extensively tested, so only carriers with affinity for specific cancer cell types may be available. Since each cancer is a unique mutation of a patients' personal genome, and since multiple mutations of the cancer cells frequently occur in a stage 3 or 4 cancer, multiple carriers with different affinities may be required for treatment. Fortunately, many institutions have been developing such materials for many years, and our photosensitizer only requires that the carrier be selective to a cell type and that the carrier itself not have significant health risks. Still, many types and/or mutations of various cancers may not have suitable carriers available for use at any specific point in time.

While there is risk that some individuals' immune system may over-respond to the use of any drug or drug carrier (including MAb and phages), MAb are often used in cancer therapy today so pretesting for, monitoring for, and managing of this risk is becoming standard practice. Also, since large numbers of cancer cells die via apoptosis within 72 hours after a ROS driven PDT treatment, this becomes a second source of risk for initiating an excessive immune response to the free DNA and other materials released by the dying cancer cells. Risk factors must be sought out, studied, and understood during the development and assessment of any new drug.

About PDT

Photodynamic Therapy (PDT) using ROS generation from oxygen in the body and light energy is known and is use around the world. PDT is mostly approved for shallow skin cancers and other dermatological or ocular treatments. Endoscopic PDT has also been used successfully in many types of solid tumor cancer treatments with fewer observed side effects in most cases than most alternative procedures such as surgery, chemotherapy, or radiation therapy. One of the limitations of PDT has been depth of activation range of only a few millimeters, which is partly mitigated with the extreeme extinction coefficient of ICy and BrCy dyes.

The new photosensitizers we are developing generate ROS like most other PDT drugs. What is unique about what our new photosensitizers is that these photosensitizers are 10-50X more sensitive to light than other near-IR photosensitizers in the market, retain better sensitivity when loaded onto on most carriers, are easy to load on or in most carriers, and appear non-dark-toxic. These photosensitizer characteristics may someday uniquely permit non-invasive or less-invasive therapies to be used on tumors far from the skin's surface or for treating distributed cancers and pathogens.

About PSC

PSC is an abbreviated name we use in this web site to define a photosensitizer + carrier conjugate. This we define as a conjugate of a carrier (molecule or particle) containing one or more photosensitizer molecules. Conjugates of a variety of carriers using other photosensitizers have been tested and reported or published by multiple other researchers.

Our business is developing, manufacturing, and selling novel photoluminescent materials and photosensitizers, as well as licensing the use of our enabling photoluminescent labels, photosensitizers, and related technologies to organizations that will create and qualify new analytical methods, diagnostics, and therapeutics using our materials and technologies.

Therefore, we are not developing the final therapeutic drugs ourselves. We are conducting research using known MAb carriers and cancer cell lines with known affinities to the selected MAb carriers in order to understand how to effectively utilize these new photosensitizers on carriers.

In the drawings below we show phage as the example carrier, but other carriers may be easily substituted for phage.


Conceptual Sequence of Steps in Future PSC Therapy

Illustration 2

Cancer cell or pathogen next to normal cells before treatment.

Illustration 2: Cancer cell or pathogen next to normal cells before treatment
Illustration 3

PSC are introduced to the body. PSC can be introduced to the bloodstream by IV or injection. PSC could also potentially be topically introduced or absorbed through the digestive system, depending on the situation and treatment or diagnostic objective.

The PSC flow past most of the cells in the body and do not attach, but the phage carriers with matched binding sites adhere with high affinity to the surface of the targeted cancer cells or pathogens. Many PSC are lost due to filtering by the liver, kidneys, and potentially other organs depending on the carrier used. and individual patient characteristics, but here we show only the PSC that attach to the targeted cells or pathogens.

After as little as 30-120 minutes, the body should remove almost all of the unattached PSC, leaving phage covering the targeted cells, but minimally or not attached to non-targeted cells.

Illustration 3: PSC are introduced to the body.


Illustration 4

Activating light for the fluorescent reporters and/or the photodynamic reactive materials in the PSC is applied to the skin surface or by light probe in the vicinity of the area to the treated. Accurate placement of probes should be less important for most treatments than required for conventional photodynamic therapy.

The selected light penetrates though controlled depths of tissue, depending on the intensity and wavelengths used. Near-infra red light can penetrate long distances, providing light energy through large volumes of tissue. PSC therapy could potentially be effective through over 4 inches inches of tissue, depending on the tissue type and other parameters, especially if light is provided over large areas on all sides of the region to be exposed. Skin pigment is less of a factor for near-IR light than for visible light wavelengths.

PSC efficiently absorb this light. PSC with or without added fluorescent reporters can absorb the externally supplied light and then emit their own unique color or spectrum light. This fluorescent emitted light or light pulse induced ultrasonic and be detected, letting the physician (local or remote via telecommunications) know if the expected localized concentration of PSC has occurred.

PSC should be able to uniquely tell the physician if it is likely to be effective before light activation and how effective the treatment has been after light activation of the PSC.

Illustration 4: Activating light for the fluorescent reporters and/or the photodynamic reactive materials in the PSC is applied to the skin surface or by alight probe in the vicinity of the area to the treated. The area illuminated may be large and cover multiple sides of the portion of the body being treated to increase the light intensity deeper in the tissue, further away from the light source. These PSC efficiently absorb the externally supplied near-IR light and then re-emit their own unique wavelength light, letting the physician know if the expected localized concentration of PSC has occurred.
Illustration 5

During additional activating light exposure of the PSC, the PSC “continuously manufacturers” reactive oxygen species (ROS) such as singlet oxygen and super oxide anion from the interstitial oxygen present in the body. This drug manufacturing on the target cells occurs until the light is turned off or the PSC stops producing ROS. Stopping ROS generation after a desired ROS dose is obtained regardless of light intensity or duration of exposure is an expected advantage of our planned PSC technology. The ROS is the primary active chemical that damages the target cells, not the PSC itself.

Some of our photosensitizers-in-development can also induce other cell killing reactions that would be useful in low-oxygen tumor environments.

Illustration 5: During additional activating light exposure of the PSC, the photosensitizer “continuously manufacturers” reactive oxygen species (ROS) such as singlet oxygen and super oxide anion from the interstitial oxygen present in the body. ROS generation occurs until the light is turned off or the PSC photodegrades and stops producing ROS.
Illustration 6

After treatment, the targeted cancer cells or pathogens should quickly stop dividing and then die over a few hours to a few days of time. These dead cells or dead pathogens should be reabsorbed by the body or excreted. Seriously damaged cancer cells with PSC attached would also be targets for attack by the body’s immune system, providing a secondary treatment benefit. Even surviving pathogens subjected to low dose PDT deactivation treatments would also likely be less able to reproduce, and may have their ability to produce toxins reduced.

The PSC can continue to be monitored as was done in Illustration 4, with or without the photodynamic compounds present. Success of the treatment can be determined by verifying the PSC signal is dissipating. Low-dose fluorescent-tag-only or normal PSC can be used to re-decorate and reveal if the previously targeted type of cancer cells or the select pathogens remain or recover.

We are also researching a method that appears possible for our photosensitizers that would also permit optical deactivation of the PSC after treatment or in regions where PDT is not desired. Success in developing this technology would reduce a patient's in-clinic time requirement and reduce the risks associated with possible post-treatment sunlight exposure.



Illustration 6: After treatment, the targeted cancer cells or pathogens slowly die over a few hours to a few days of time. These dead cells or pathogens may be reabsorbed or excreted.

Many MAb carriers and most other carriers with selective affinity for the certain targeted cancer cell types have been identified, characterized, and developed by researchers around the world. Patients that could benefit from each specific PSC could be identified based on analysis of the biopsied cancer cell affinity(s) and lab testing for the biopsied cells with a matrix of many potential carriers. Many possible selective affinity carriers targeting different pathogens or cancer variants can be developed and utilized as a separate drug, but all these different drugs could carry the same photosensitizer.

The PSC’s non-reactivity except where light is present should allow the liver and other organs to potentially accumulate and/or excrete the PSCN without damage or dangerous side effects. There will likely be risks of immune responses to PSC and the byproducts of treated cancer cells or pathogens, and other effects that need to be carefully studied.

Because PSC is only chemically active for short periods of time during the light exposure and are expected to be quickly eliminated from the body, long term pathogen resistance should be more difficult to develop than with conventional chemotherapy drugs and antibiotics. Several publications have evaluated pathogen resistance to the ROS generated by photosensitizers, and no resistance has yet been shown to develop. Pathogen resistance resulting from loss of affinity to specific carrier is still a risk, if a carrier is used with the photosensitizer.

Some bacteria and virus might be effectively targeted by some of our photosensitizers even without the use of a selective carrier and pose little risk to human or animal cells, but this work is still at a very early stage.

Novel Materials In Development

Multiple materials are under development and being characterized, but unique new materials already show significant promise for:

  • Additional photoluminescent labels or probes with even higher sensitivities and brightness.

  • Highly engineered photodynamic (PDT) materials with high sensitivity and reactivity to proteins that can enable anti-cancer or antibiotic activation several inches through tissue with minimal visual light spectrum sensitivity

  • Further PSC technology development for photodynamic treatment of cancer, pathogens, and other targeted materials.

  • Novel activating light sources and sensor matrices to activate and provide feedback from novel targeting PSC. Low-cost, large-area near-IR sources with feedback are a primary focus.