Analysis of Nanomaterials on Biological and Environmental Systems and New Analytical Methods for Improved Detection.

The advancing field of nanoscience has produced lower mass, smaller size, and expanded chemical composition nanoparticles over recent years. These new nanoparticles have challenged traditional analytical methods of qualification and quantification. Such advancements in nanoparticles and nanomaterials have captured the attention of toxicologists with concerns regarding the environment and human health impacts. Given that nanoparticles are only limited by size (1-100 nm), their chemical and physical characteristics can drastically change and thus alter their overall nanotoxicity in unpredictable ways. A significant limitation to the development of nanomaterials is that traditional regulatory and scientific methods used to assess the biological and environmental toxicity of chemicals do not generally apply to the assessment of nanomaterials. Significant research effort has been initiated, but much more is still needed to develop new and improved analytical measurement methods for detecting and quantitating nanomaterials in biological and environmental systems.

Development of Biodegradable GQDs-hMSNs for Fluorescence Imaging and Dual Cancer Treatment via Photodynamic Therapy and Drug Delivery.

Recently, nano-based cancer therapeutics have been researched and developed, with some nanomaterials showing anticancer properties. When it comes to cancer treatment, graphene quantum dots (GQDs) contain the ability to generate 1O2, a reactive oxidative species (ROS), allowing for the synergistic imaging and photodynamic therapy (PDT) of cancer. However, due to their small particle size, GQDs struggle to remain in the target area for long periods of time in addition to being poor drug carriers. To address this limitation of GQDs, hollow mesoporous silica nanoparticles (hMSNs) have been extensively researched for drug delivery applications. This project investigates the utilization and combination of biomass-derived GQDs and Stöber silica hMSNs to make graphene quantum dots-hollow mesoporous silica nanoparticles (GQDs-hMSNs) for fluorescent imaging and dual treatment of cancer via drug delivery and photodynamic therapy (PDT). Although the addition of hMSNs made the newly synthesized nanoparticles slightly more toxic at higher concentrations, the GQDs-hMSNs displayed excellent drug delivery using fluorescein (FITC) as a mock drug, and PDT treatment by using the GQDs as a photosensitizer (PS). Additionally, the GQDs retained their fluorescence through the surface binding to hMSNs, allowing them to still be used for cell-labeling applications.

Graphene/gold nanoparticle composites for ultrasensitive and versatile biomarker assay using single-particle inductively-coupled plasma/mass spectrometry.

An ultrasensitive and versatile assay for biomarkers has been developed using graphene/gold nanoparticles (AuNPs) composites and single-particle inductively-coupled plasma/mass spectrometry (spICP-MS). Thrombin was chosen as a model biomarker for this study. AuNPs modified with thrombin aptamers were first non-selectively adsorbed onto the surface of graphene oxide (GO) to form GO/AuNPs composites. In the presence of thrombin, the AuNPs desorbed from the GO/AuNPs composites due to a conformation change of the thrombin aptamer after binding with thrombin. The desorbed AuNPs were proportional to the concentration of thrombin and could be quantified by spICP-MS. By counting the individual AuNPs in the spICP-MS measurement, the concentration of thrombin could be determined. This assay achieved an ultralow detection limit of 4.5 fM with a broad linear range from 10 fM to 100 pM. The method also showed excellent selectivity and reproducibility when a complex protein matrix was evaluated. Furthermore, the diversity and ready availability of ssDNA ligands make this method a versatile new technique for ultrasensitive detection of a wide variety of biomarkers in clinical diagnostics.

Nanozymes-Hitting the Biosensing "Target".

Nanozymes are a class of artificial enzymes that have dimensions in the nanometer range and can be composed of simple metal and metal oxide nanoparticles, metal nanoclusters, dots (both quantum and carbon), nanotubes, nanowires, or multiple metal-organic frameworks (MOFs). They exhibit excellent catalytic activities with low cost, high operational robustness, and a stable shelf-life. More importantly, they are amenable to modifications that can change their surface structures and increase the range of their applications. There are three main classes of nanozymes including the peroxidase-like, the oxidase-like, and the antioxidant nanozymes. Each of these classes catalyzes a specific group of reactions. With the development of nanoscience and nanotechnology, the variety of applications for nanozymes in diverse fields has expanded dramatically, with the most popular applications in biosensing. Nanozyme-based novel biosensors have been designed to detect ions, small molecules, nucleic acids, proteins, and cancer cells. The current review focuses on the catalytic mechanism of nanozymes, their application in biosensing, and the identification of future directions for the field.

A graphene oxide-based fluorescence assay for the sensitive detection of DNA exonuclease enzymatic activity.

The 3'-5' exonuclease enzyme plays a dominant role in multiple pivotal physiological activities, such as DNA replication and repair processes. In this study, we designed a sensitive graphene oxide (GO)-based probe for the detection of exonuclease enzymatic activity. In the absence of Exo III, the strong π-π interaction between the fluorophore-tagged DNA and GO causes the efficient fluorescence quenching via a fluorescence resonance energy transfer (FRET). In contrast, in the presence of Exo III, the fluorophore-tagged 3'-hydroxyl termini of the DNA probe was digested by Exo III to set the fluorophore free from adsorption when GO was introduced, causing an inefficient fluorescence quenching. As a result, the fluorescence intensity of the sensor was found to be proportional to the concentration of Exo III; towards the detection of Exo III, this simple GO-based probe demonstrated a highly sensitive and selective linear response in the low detection range from 0.01 U mL-1 to 0.5 U mL-1 and with the limit of detection (LOD) of 0.001 U mL-1. Compared with other fluorescent probes, this assay exhibited superior sensitivity and selectivity in both buffer and fetal bovine serum samples, in addition to being cost effective and having a simple setup.

Effects of silica nanoparticles on endolysosome function in primary cultured neurons 1.

Silica nanoparticles (SiNPs) have been used as vehicles for drug delivery, molecular detection, and cellular manipulations in nanoneuromedicine. SiNPs may cause adverse effects in the brain including neurotoxicity, neuroinflammation, neurodegeneration, and enhancing levels of amyloid beta (Aß) protein-all pathological hallmarks of Alzheimer's disease. Therefore, the extent to which SiNPs influence Aß generation and the underlying mechanisms by which this occurs deserve investigation. Our studies were focused on the effects of SiNPs on endolysosomes which uptake, traffic, and mediate the actions of SiNPs. These organelles are also where amyloidogenesis largely originates. We found that SiNPs, in primary cultured hippocampal neurons, accumulated in endolysosomes and caused a rapid and persistent deacidification of endolysosomes. SiNPs significantly reduced endolysosome calcium stores as indicated by a significant reduction in the ability of the lysosomotropic agent glycyl-l-phenylalanine 2-naphthylamide (GPN) to release calcium from endolysosomes. SiNPs increased Aß1-40 secretion, whereas 2 agents that acidified endolysosomes, ML-SA1 and CGS21680, blocked SiNP-induced deacidification and increased generation of Aß1-40. Our findings suggest that SiNP-induced deacidification of and calcium release from endolysosomes might be mechanistically linked to increased amyloidogenesis. The use of SiNPs might not be the best nanomaterial for therapeutic strategies against Alzheimer's disease and other neurological disorders linked to endolysosome dysfunction.

Aggregation-based determination of mercury(II) using DNA-modified single gold nanoparticle, T-Hg(II)-T interaction, and single-particle ICP-MS.

An ultrasensitive assay is described for the detection and determination of Hg2+(aq) in water samples based on single-particle inductively-coupled plasma/mass spectrometry (spICP-MS). In the presence of Hg2+(aq), AuNPs modified with a segment of single-stranded DNA aggregate due to the formation of the well-known thymine (T)-Hg2+-T complex. Single particle (sp) ICP-MS is used quantify the degree of aggregation by the overall decrease in number of detected AuNPs or NP aggregates. Compared with most other Hg2+ assays that use the same principle of aggregation-dispersion with DNA modified AuNPs, this method has a much lower detection limit of (0.031 ng L-1, 155 fM) and a wider (10,000-fold) linear range (up to 1 µg L-1). The method also showed good practical potential because of its minimal interference from the water sample matrix. Graphical abstractSchematic representation of Hg2+ determination by using modified AuNP probes measured by spICP-MS. AuNPs pulses detected in ICP-MS is relative to the aggregation status of AuNPs based on thymine-Hg2+-thymine interaction.

Study of Fluorescence Quenching Ability of Graphene Oxide with a Layer of Rigid and Tunable Silica Spacer.

The fluorescence quenching property of graphene oxide (GO) has been newly demonstrated and applied for fluorescence imaging and biosensing. In this work, a new nanostructure was designed for effectively studying the quenching ability of GO. The key element in this design is the fabrication of a layer of rigid and thickness adjustable silica spacer for manipulating the distance between the GO and fluorophores. First, a silica core modified with organic dye molecules was prepared, followed by the formation of a silica shell with a tunable thickness. Afterward, the GO was wrapped around silica nanoparticles based on the electrostatic interaction between the negatively charged GO and positively charged silica. The quenching efficiency of GO to different dye molecules was studied at various spacer thicknesses and varying concentrations of GO. Fluorescence lifetime of fluorophores was measured to determine the quenching mechanism. We found that the quenching efficiency of GO was still around 30% when the distance between dyes and GO was increased to more than 30 nm, which indicated the long-distance quenching ability of GO and confirmed the previous theoretical calculation. The quenching mechanisms were proposed schematically based on our experimental results. We expected that the proposed nanostructure could act as a feasible model for studying GO quenching property and shed light on designing GO-based fluorescence sensing systems.

Gold-nanoparticle-decorated silica nanorods for sensitive visual detection of proteins.

We report a rapid and highly sensitive approach based on gold-nanoparticle-decorated silica nanorods (GNP-SiNRs) label and lateral-flow strip biosensor (LFSB) for visually detecting proteins. Owing to its biocompatibility and convenient surface modification, SiNRs were used as carriers to load numerous GNPs, and the GNP-SiNRs were used as labels for the lateral-flow assay. The LFSB detection limit was lowered 50 times compared to the traditional GNP-based lateral-flow assay. Rabbit IgG was used as a model target to demonstrate the proof-of-concept. Sandwich-type immunoreactions were performed on the immunochromatographic strips, and the accumulation of GNP-SiNRs on the test zone produced the characteristic colored bands, enabling visual detection of proteins without instrumentation. The quantitative detection was performed by reading the intensities of the colored bands with a portable strip reader. The response of the optimized device was highly linear for the range of 0.05-2 ng mL(-1), and the detection limit was estimated to be 0.01 ng mL(-1). The GNP-SiNR-based LFSB, thus, offered an ultrasensitive method for rapidly detecting trace amounts of proteins. This method has a potential application with point-of-care screening for clinical diagnostics and biomedical research.

Au-Silica nanowire nanohybrid as a hyperthermia agent for photothermal therapy in the near-infrared region.

Nanomaterial-based photothermal therapy has shown great potential for efficient cancer treatment. Here, we report a new hyperthermia agent, Au-silica nanowire nanohybrid (Au-SiNW nanohybrid) with tunable optical properties, for photothermal therapy. The unique feature of the synthetic method is no need of surface modification of SiNWs for the direct deposition of Au seeds, which can avoid complicated synthetic procedures and improve the reproducibility. The Au-SiNW nanohybrid can generate significant amount of heat upon irradiation in the near-infrared (NIR) region for inducing thermal cell death. Moreover, compared to reported hyperthermia nanomaterials, the new nanohybrid requires a much lower laser irradiation density of 0.3 W/cm(2) for destroying cancer cells. A549 lung cancer cells were used for in vitro photothermal study. The nanohybrid showed excellent in vitro biocompatibility by using a 96-nonradioactive-cell proliferation assay. Even at a high concentration of 0.500 mg/mL nanohybrid, over 80% cells were alive. In contrast, almost all the cells were killed when NIR irradiation was applied at a concentration of 0.100 mg/mL nanohybrid. The Au-SiNW nanohybrid may become a promising hyperthermia agent.

Ultrasensitive detection of 3'-5' exonuclease enzymatic activity using molecular beacons.

An ultrasensitive and rapid turn-on fluorescence assay has been developed for the detection of 3'-5' exonuclease activity of exonuclease III (Exo III) using molecular beacons (MBs). This method has a linear detection range from 0.04 to 8.00 U mL(-1) with a limit of detection of 0.01 U mL(-1). In order to improve the selectivity of the method, a dual-MB system has been developed to distinguish between different exonucleases. With the introduction of two differently designed MBs which respond to different exonucleases, the T5 exonuclease, Exo III and RecJf exonucleases can be easily distinguished from each other. Furthermore, fetal bovine serum and fresh mouse serum were used as complex samples to investigate the feasibility of the dual-MB system for the detection of the enzymatic activity of Exo III. As a result, the dual-MB system showed a similar calibration curve for the detection of Exo III as in the ideal buffer solution. The designed MB probe could be a potential sensor for the detection of Exo III in biological samples.

Recent development of silica nanoparticles as delivery vectors for cancer imaging and therapy.

In spite of significant advances in early detection and combined treatments, a number of cancers are often diagnosed at advanced stages and thereby carry a poor prognosis. Developing novel prognostic biomarkers and targeted therapies may offer alternatives for cancer diagnosis and treatment. Recent rapid development of nanomaterials, such as silica based nanoparticles (SiNPs), can just render such a promise. In this article, we attempt to summarize the recent progress of SiNPs in tumor research as a novel delivery vector. SiNP-assisted imaging techniques are used in cancer diagnosis both in vitro and in vivo. Meanwhile, SiNP-mediated drug delivery can efficiently treat tumor by carrying chemotherapeutic agents, photosensitizers, photothermal agents, siRNA, and gene therapeutic agents. Finally, SiNPs that contain at least two different functional agents may be more powerful for both tumor imaging and therapy. FROM THE CLINICAL EDITOR: This paper summarizes recent progress on the field of silica nanoparticles research as novel delivery vectors for cancer-specific imaging as well as drug delivery of chemotherapeutics, photosensitizers, photothermal agents, siRNA, and gene therapy agents.

An Unprecedented Metal Distribution in Silica Nanoparticles Determined by Single-Particle Inductively Coupled Plasma Mass Spectrometry.

Metal-containing nanoparticles are now common in applications ranging from catalysts to biomarkers. However, little research has focused on per-particle metal content in multicomponent nanoparticles. In this work, we used single-particle inductively coupled plasma mass spectrometry (ICP-MS) to determine the per-particle metal content of silica nanoparticles doped with tris(2,2'-bipyridyl)ruthenium(II). Monodispersed silica nanoparticles with varied Ru doping levels were prepared using a water-in-oil microemulsion method. These nanoparticles were characterized using common bulk-sample methods such as absorbance spectroscopy and conventional ICP-MS, and also with single-particle ICP-MS. The results showed that averaged concentrations of metal dopant measured per-particle by single-particle ICP-MS were consistent with the bulk-sample methods over a wide range of dopant levels. However, the per-particle amount of metal varied greatly and did not adhere to the usual Gaussian distribution encountered with one-component nanoparticles, such as gold or silver. Instead, the amount of metal dopant per silica particle showed an unexpected geometric distribution regardless of the prepared doping levels. The results indicate that an unusual metal dispersal mechanism is taking place during the microemulsion synthesis, and they challenge a common assumption that doped silica nanoparticles have the same metal content as the average measured by bulk-sample methods.

Development of gold nanoparticle-enhanced fluorescent nanocomposites.

A gold nanoparticle-enhanced fluorescent nanocomposite was developed. The designed nanocomposite contained a spherical gold nanoparticle core, a thin PVP coating layer, a silica spacer, and a fluorescent dye layer in the silica matrix. The dye molecules were conjugated to a polymer to be effectively doped in the nanocomposites. Different sized gold nanoparticle cores were used while the spacer thickness was varied. The function of the PVP layer in the fabrication of the nanocomposites was discussed. The fluorescence enhancement effects of the metal core size (gold nanoparticles) and the distance between the fluorescent molecules and the metal core were systematically studied. A series of control experiments were conducted to ensure the accuracy of the fluorescence enhancement measurement. The results showed that the developed nanocomposite can effectively enhance the fluorescence signal of the doped dye conjugates. An enhancement factor of 9.2 was obtained when the nanocomposite contained a 13.7 ± 1.3 nm gold nanoparticle core and a 36.6 ± 4.4 nm silica spacer. It is expected that the developed nanocomposite could be an effective model for studying various effects and the mechanism of metal-enhanced fluorescence at the nanoscale.

A reversible fluorescent logic gate for sensing mercury and iodide ions based on a molecular beacon.

A simple, rapid, and reversible fluorescent DNA INHIBIT logic gate has been developed for sensing mercury (Hg(2+)) and iodide (I(-)) ions based on a molecular beacon (MB). In this logic gate, a mercury ion was introduced as the first input into the MB logic gate system to assist in the hybridization of the MB with an assistant DNA probe through the thymine-Hg(2+)-thymine interaction, which eventually restored the fluorescence of MB as the output. With this signal-on process, mercury ions can be detected with a limit of detection as low as 7.9 nM. Furthermore, when iodide ions were added to the Hg(2+)/MB system as the second input, the fluorescence intensity decreased because Hg(2+) in the thymine-Hg(2+)-thymine complex was grabbed by I(-) due to a stronger binding force. Iodide ions can be detected with a limit of detection of 42 nM. Meanwhile, we studied the feasibility and basic performance of the DNA INHIBIT logic gate, optimized the logic gate conditions, and investigated its sensitivity and selectivity. The results showed that the MB based logic gate is highly selective and sensitive for the detection of Hg(2+) and I(-) over other interfering cations and anions.

A target-induced fluorescent nanoparticle for in situ monitoring of Zn(II).

A target-induced fluorescent silica nanoparticle has been developed for the identification, enrichment and in situ determination of trace amounts of zinc(II). The nanoparticle combines the advantages of target-induced fluorescent compounds and the small size of the nanomaterial to produce a new, smarter nanosignaling material that is capable of selectively enriching a target and detecting a specific binding process in one step. As the target analyte, Zn(II), changes the fluorescence characteristics of the nanoparticle and effectively 'turns on' the fluorescence signal, no separation step is needed to confirm or quantify the binding process. The designed nanoparticle was characterized by several aspects prior to monitoring of Zn(II) in situ. The interferences from common metal ions were studied in detail. The photostability and reversibility of the sensing materials were investigated as well. The ability of this nanoparticle to detect the target Zn(II) provides a great advantage for in situ monitoring targets in biological samples under the fluorescence microscope.

Streamlined synthesis of potential dual-emissive fluorescent silicon quantum dots (SiQDs) for cell imaging.

One of the current challenges of working with nanomaterials in bioapplications is having a tool that is biocompatible (non-toxic) and produces stable, intense fluorescence for bioimaging. To address these challenges, we have developed a streamlined and one-pot synthetic route for silicon-based quantum dots (SiQDs) using a hydrothermal method. Part of our unique approach for designing the SiQDs was to incorporate (3-aminopropyl) triethoxysilane (APTES), which is an amphipathic molecule with hydroxyl and amine functional groups available for modification. In order to reduce the toxicity of APTES, we chose glucose as a reducing agent for the reaction. The resulting SiQDs produced potent, stable, potential dual-emissive fluorescence emission peaks in the visible and near-infrared (NIR) ranges. Both peaks could be used as distinguishing fluorescence signals for bioimaging, separately or in combination. The physical and optical properties of the SiQDs were determined under a range of environmental conditions. The morphology, surface composition, and electronic structure of the SiQDs were characterized using high resolution-transmission electronic microscopy (HR-TEM), energy dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The stability of the SiQDs was evaluated under a wide range of pHs. The biocompatibility and imaging potential of the SiQDs were tested in microvascular endothelial cells (MVEC), neural stem cells (NSC), and RAW 264.7 macrophage cells. The images obtained revealed different subcellular localizations, particularly during cell division, with distinct fluorescence intensities. The results demonstrated that SiQDs are a promising, non-toxic labeling tool for a variety of cell types, with the added advantage of having dual emission peaks both in visible and NIR ranges for bioimaging.

One-Pot Synthesis of Ruthenium-Based Nanocatalyst Using Reduced Graphene Oxide as Matrix for Electrochemical Synthesis of Ammonia.

Conventional ammonia production consumes significant energy and causes enormous carbon dioxide (CO2) emissions globally. To lower energy consumption and mitigate CO2 emissions, a facile, environmentally friendly, and cost-effective one-pot method for the synthesis of a ruthenium-based nitrogen reduction nanocatalyst has been developed using reduced graphene oxide (rGO) as a matrix. The nanocatalyst synthesis was based on a single-step simultaneous reduction of RuCl3 into ruthenium-based nanoparticles (Ru-based NPs) and graphene oxide (GO) into rGO using glucose as the reducing agent and stabilizer. The obtained ruthenium-based nanocatalyst with rGO as a matrix (Runano-based/rGO) has shown much higher catalytic activity at lower temperatures and pressures for ammonia synthesis than conventional iron catalysts. The rGO worked as a promising promoter for the electrochemical synthesis of ammonia due to its excellent electrical and thermal conductivity. The developed Runano-based/rGO nanocatalyst was characterized using transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), inductively coupled plasma mass spectrometry (ICP-MS), and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the size of the Ru-based NPs on the surface of rGO was 1.9 ± 0.2 nm and the ruthenium content was 25.03 wt %. Bulk electrolysis measurements were conducted on thin-layer electrodes at various cathodic potentials in a N2-saturated 0.1 M H2SO4 electrolyte at room temperature. From the chronoamperometric measurements, the maximum faradic efficiency (F.E.) of 2.1% for ammonia production on the nanostructured Runano-based/rGO electrocatalyst was achieved at a potential of -0.20 V vs reversible hydrogen electrode (RHE). This electrocatalyst has attained a superior ammonia production rate of 9.14 µg·h-1·mgcat.-1. The results demonstrate the feasibility of reducing N2 into ammonia under ambient conditions and warrant further exploration of the nanostructured Runano-based/rGO for electrochemical ammonia synthesis.

Upconversion nanomaterials: synthesis, mechanism, and applications in sensing.

Upconversion is an optical process that involves the conversion of lower-energy photons into higher-energy photons. It has been extensively studied since mid-1960s and widely applied in optical devices. Over the past decade, high-quality rare earth-doped upconversion nanoparticles have been successfully synthesized with the rapid development of nanotechnology and are becoming more prominent in biological sciences. The synthesis methods are usually phase-based processes, such as thermal decomposition, hydrothermal reaction, and ionic liquids-based synthesis. The main difference between upconversion nanoparticles and other nanomaterials is that they can emit visible light under near infrared irradiation. The near infrared irradiation leads to low autofluorescence, less scattering and absorption, and deep penetration in biological samples. In this review, the synthesis of upconversion nanoparticles and the mechanisms of upconversion process will be discussed, followed by their applications in different areas, especially in the biological field for biosensing.

Development of Red-Emissive Porphyrin Graphene Quantum Dots (PGQDs) for Biological Cell-Labeling Applications.

Red and near-infrared emission is a highly desirable feature for fluorescent nanoparticles in biological applications mainly due to longer wavelengths more easily being able to deeply penetrate tissues, organs, skin, and other organic components, while less autofluorescence interference would be produced. Additionally, graphene quantum dots (GQDs) that contain unique optical and electrical features have been targeted for their use in cell labeling applications as well as environmental analysis. Their most desirable features come in the form of low toxicity and biocompatibility; however, GQDs are frequently reported to have blue or green emission light and not the more advantageous red/NIR emission light. Furthermore, porphyrins are a subgroup of heterocyclic macrocycle organic compounds that are also naturally occurring pigments in nature that already contain the desired red-emission fluorescence. Therefore, porphyrins have been used previously to synthesize nanomaterials and for nanoparticle doping in order to incorporate the red/NIR emission light property into particles that otherwise do not contain the desired emission light. Meso-tetra(4-carboxyphenyl)porphine (TCPP) is one type of porphyrin with a large conjugated π-electron system and four carboxyl groups on its exterior benzene rings. These two key characteristics of TCPP make it ideal for incorporation into GQDs, as it would design and synthesize red-emissive material as well as give rise to excellent water solubility. In this work, TCPP is used in tangent with cis-cyclobutane-1,2-dicarboxylic acid (CBDA-2), a biomass derived organic molecule, to synthesize "green" porphyrin-based graphene quantum dots (PGQDs) with red-emission. The obtained PGQDs were characterized by various analytical methods. Utilizing TEM, HRTEM, and DLS the size distribution of the particles was determined to be 7.9 ± 4.1, well within the quantum dot range of 2-10 nm. FT-IR, XPS, and XRD depicted carbon, nitrogen, and oxygen as the main elemental components with carbon being in the form of graphene and the main porphyrin ring of TCPP remaining present in the final PGQDs product. Lastly, absorption and fluorescence spectroscopy determined the excitation wavelength at 420 nm and the emission at 650 nm which was successfully utilized in the imaging of HeLa cells using confocal microscopy.