Self-adaptive non-covalent albumin-binding near-infrared probe conjugates enabling precise sentinel lymph node metastasis illumination and primary tumor imaging

Tumor sentinel lymph node(SLN)metastasis plays a vital role in tumor staging and therapeutic decision-making process.However,precise diagnosis of primary tumors and lymphatic metastases is still hindered by low imaging resolution and poor photostability of fluorescent probes.Herein,we report three novel IR820-fatty acid(FA)conjugates(IR-OA,IR-LA,and IR-PA)for precise lymphatic metastasis illumination and primary tumor diagnosis.The IR-FA conjugates are able to non-covalently bound to albumin in vivo,and the fluorescence quantum yield is significantly enhanced after incubation with bovine serum albumin(BSA)in vitro.Moreover,the BSA-IR-FA conjugates display large Stokes shift(>120 nm),dramatically improving in vivo imaging resolution.Among them,IR-PA demonstrates distinct advantage over IR-OA,IR-LA,and IR-maleimide(MAL)(fluorescent probe previously reported by our group)in terms of fluorescence quantum yield,photostability,and imaging resolution.As a result,IR-PA exhibits satisfactory imaging results with high fluorescence intensity and imaging resolution in sentinel lymph node metastasis illumination and primary tumor location.Our findings provide a self-adaptive albumin-binding near-infrared probe conjugate for accurate diagnosis of primary tumors and lymphatic metastases.

Functional near-infrared spectroscopy in non-invasive neuromodulation

Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson’s disease,and mental disorders.Although significant advances have been made in neuromodulation technologies,the identification of optimal neurostimulation paramete rs including the co rtical target,duration,and inhibition or excitation pattern is still limited due to the lack of guidance for neural circuits.Moreove r,the neural mechanism unde rlying neuromodulation for improved behavioral performance remains poorly understood.Recently,advancements in neuroimaging have provided insight into neuromodulation techniques.Functional near-infrared spectroscopy,as a novel non-invasive optical brain imaging method,can detect brain activity by measuring cerebral hemodynamics with the advantages of portability,high motion tole rance,and anti-electromagnetic interference.Coupling functional near-infra red spectroscopy with neuromodulation technologies offe rs an opportunity to monitor the cortical response,provide realtime feedbac k,and establish a closed-loop strategy integrating evaluation,feedbac k,and intervention for neurostimulation,which provides a theoretical basis for development of individualized precise neuro rehabilitation.We aimed to summarize the advantages of functional near-infra red spectroscopy and provide an ove rview of the current research on functional near-infrared spectroscopy in transcranial magnetic stimulation,transcranial electrical stimulation,neurofeedback,and braincomputer interfaces.Furthermore,the future perspectives and directions for the application of functional near-infrared spectroscopy in neuromodulation are summarized.In conclusion,functional near-infrared spectroscopy combined with neuromodulation may promote the optimization of central pellral reorganization to achieve better functional recovery form central nervous system diseases.

Near-infrared spectroscopy in schizophrenia:A bibliometric perspective

BACKGROUND Compared with current methods used to assess schizophrenia,near-infrared spectroscopy(NIRS)has the advantages of providing noninvasive and real-time monitoring of functional activities of the brain and providing direct and objective assessment information.AIM To explore the research field of NIRS in schizophrenia from the perspective of bibliometrics.METHODS The Web of Science Core Collection was used as the search tool,and the last search date was April 21,2024.Bibliometric indicators,such as the numbers of publications and citations,were recorded.Bibliometrix and VOS viewer were used for visualization analysis.RESULTS A total of 355 articles from 105 journals were included in the analysis.The overall trend of the number of research publications increased.Schizophrenia Research was identified as an influential journal in the field.Kasai K was one of the most influential and productive authors in this area of research.The University of Tokyo and Japan had the highest scientific output for an institution and a country,respectively.The top ten keywords were“schizophrenia”,“activation”,“near-infrared spectroscopy”,“verbal fluency task”,“cortex”,“brain,performance”,“workingmemory”,“brain activation”,and“prefrontal cortex”.CONCLUSION Our study reveals the evolution of knowledge and emerging trends in the field of NIRS in schizophrenia.the research focus is shifting from underlying disease characteristics to more in-depth studies of brain function and physiological mechanisms.

Achieving broadband near-infrared luminescence in Cr^(3+)-Activated Y_(2)Mg_(2)Al_(2)Si_(2)O_(12)phosphors via multi-site occupancy

Cr^(3+)-activated near-infrared(NIR)phosphors are key for NIR phosphor-converted light emitting diodes(NIR pc-LED).While,the site occupancy of Cr^(3+)is one of the debates that have plagued researchers.Herein,Y2Mg2Al2-Si_(2)O1_(2)(YMAS)with multiple cationic sites is chosen as host of Cr^(3+)to synthesize YMAS:xCr^(3+)phosphors.In YMAS,Cr^(3+)ions occupy simultaneously Al/SiO4 tetrahedral,Mg/AlO6 octahedral,and Y/MgO8 dodecahedral sites which form three luminescent centers named as Cr1,Cr2,and Cr3,respectively.Cr1 and Cr2 relate to an intermediate crystal field,with transitions of^(2)E→^(4)A_(2)and^(4)T_(2)→^(4)A_(2)occurring simultaneously.As Cr^(3+)concentration increases,the^(4)T_(2)→^(4)A_(2)transition becomes more pronounced in Cr1 and Cr2,resulting in a red-shift and broadband emission.Cr3 consistently behaves a weak crystal field and exhibits the broad and long-wavelength emission.Wide-range NIR emission centering at 745 nm is realized in YMAS:0.03Cr^(3+)phosphor.This phosphor has high internal quantum efficiency(IQE?86%)and satisfying luminescence thermal stability(I423 K?70.2%).Using this phosphor,NIR pc-LEDs with 56.6 mW@320 mA optical output power is packaged and applied.Present study not only demonstrates the Cr^(3+)multi-site occupancy in a certain oxide but also provides a reliable approach via choosing a host with diverse cationic sites and local environments for Cr^(3+)to achieve broadband NIR phosphors.

Rapid determination of oil content of single peanut seed by near-infrared hyperspectral imaging

Oil content is a crucial indicator for evaluating the quality of peanuts.A rapid and non-destructive method to determine oil content of individual peanut seed can provide robust technical support for breeding high-oil-content peanut varieties.In this study,we established a rapid determination method using near-infrared hyperspectral imaging and chemometrics to assess the oil content of single peanut seed.After selecting key wavelengths through competitive adaptive reweighted sampling(CARS),uninformative variable elimination(UVE),and random frog(RF),we constructed an oil content calibration model based on partial least squares regression for single peanut seed.Validation results demonstrated that the correlation coefficient was 0.8393 with a root mean square error of 1.7771 in the calibration set,while it was 0.7915 with a root mean square error of 2.2943 in the independent prediction set.Most samples exhibited relative errors below 5%,confirming the reliability of this model in predicting oil content of single peanut seed.

Spatial sensitivity to absorption changes for various near-infrared spectroscopy methods:A compendium review

This compendium review focuses on the spatial distribution of sensitivity to localized absorption changes in optically diffuse media,particularly for measurements relevant to near-infrared spectroscopy.The three temporal domains,continuous wave,frequency domain,and time domain,each obtain different optical data types whose changes may be related to effective homogeneous changes in the absorption coefficient.Sensitivity is the relationship between a localized perturbation and the recovered effective homogeneous absorption change.Therefore,spatial sensitivity maps representing the perturbation location can be generated for the numerous optical data types in the three temporal domains.The review first presents a history of the past 30 years of work investigating this sensitivity in optically diffuse media.These works are experimental and theoretical,presenting one-,two-,and three-dimensional sensitivity maps for different Near-Infrared Spectroscopy methods,domains,and data types.Following this history,we present a compendium of sensitivity maps organized by temporal domain and then data type.This compendium provides a valuable tool to compare the spatial sensitivity of various measurement methods and parameters in one document.Methods for one to generate these maps are provided in Appendix A,including the code.This historical review and comprehensive sensitivity map compendium provides a single source researchers may use to visualize,investigate,compare,and generate sensitivity to localized absorption change maps.

Efficacy of multi-color near-infrared fluorescence with indocyanine green:A new imaging strategy and its early experience in laparoscopic cholecystectomy

BACKGROUND Near-infrared fluorescence imaging via using intravenous indocyanine green(ICG)has a wide range of applications in multiple surgical scenarios.In lapa-roscopic cholecystectomy(LC),it facilitates intraoperative identification of the biliary system and reduces the risk of bile duct injury.However,the usual single color fluorescence imaging(SCFI)has limitations in manifesting the fluorescence signal of the target structure when its intensity is relatively low.Moreover,sur-geons often experience visual fatigue.We hypothesized that a novel imaging stra-tegy,named multi-color fluorescence imaging(MCFI),could potentially address these issues by decreasing hepatic and background fluorescence pollution and improving biliary visualization.AIM To investigate the novel imaging strategy MCFI in LC.METHODS This was a single-center retrospective study conducted at Peking Union Medical College Hospital,Beijing,China.Patients who underwent LC from June 2022 to March 2023 by the same surgical team were enrolled.Demographic features,clinical and surgical information were collected.The clarity,visual comfort,and effectiveness of different imaging strategies were subjectively evaluated by surgeons.RESULTS A total of 155 patients were included,60 patients were in the non-ICG group in which only bright light illuminance without ICG was applied,60 patients were in the SCFI group,and 35 patients were in the MCFI group.No statist-ically significant differences were found in demographics or clinical history.Post-surgical complications were minimal in all 3 groups with no significant differences observed.MCFI improved the clarity of imaging and visual comfort.Clarity of imaging and visual comfort were improved with MCFI.CONCLUSION MCFI improves biliary visualization and reduces liver fluorescence contamination,which supports its routine use in LC.MCFI may also be a better choice than SCFI in other clinical settings.

A highly sensitive ratiometric near-infrared nanosensor based on erbium-hyperdoped silicon quantum dots for iron(Ⅲ) detection

Ratiometric fluorescent detection of iron(Ⅲ)(Fe^(3+))offers inherent self-calibration and contactless analytic capabilities.However,realizing a dual-emission near-infrared(NIR)nanosensor with a low limit of detection(LOD)is rather challenging.In this work,we report the synthesis of water-dispersible erbium-hyperdoped silicon quantum dots(Si QDs:Er),which emit NIR light at the wavelengths of 810 and 1540 nm.A dual-emission NIR nanosensor based on water-dispersible Si QDs:Er enables ratiometric Fe^(3+)detection with a very low LOD(0.06μM).The effects of pH,recyclability,and the interplay between static and dynamic quenching mechanisms for Fe^(3+)detection have been systematically studied.In addition,we demonstrate that the nanosensor may be used to construct a sequential logic circuit with memory functions.

Cortical activity in patients with high-functioning ischemic stroke during the Purdue Pegboard Test:insights into bimanual coordinated fine motor skills with functional near-infrared spectroscopy

After stroke,even high-functioning individuals may experience compromised bimanual coordination and fine motor dexterity,leading to reduced functional independence.Bilateral arm training has been proposed as a promising intervention to address these deficits.However,the neural basis of the impairment of functional fine motor skills and their relationship to bimanual coordination performance in stroke patients remains unclear,limiting the development of more targeted interventions.To address this gap,our study employed functional near-infrared spectroscopy to investigate cortical responses in patients after stroke as they perform functional tasks that engage fine motor control and coordination.Twenty-four high-functioning patients with ischemic stroke(7 women,17 men;mean age 64.75±10.84 years)participated in this cross-sectional observational study and completed four subtasks from the Purdue Pegboard Test,which measures unimanual and bimanual finger and hand dexterity.We found significant bilateral activation of the sensorimotor cortices during all Purdue Pegboard Test subtasks,with bimanual tasks inducing higher cortical activation than the assembly subtask.Importantly,patients with better bimanual coordination exhibited lower cortical activation during the other three Purdue Pegboard Test subtasks.Notably,the observed neural response patterns varied depending on the specific subtask.In the unaffected hand task,the differences were primarily observed in the ipsilesional hemisphere.In contrast,the bilateral sensorimotor cortices and the contralesional hemisphere played a more prominent role in the bimanual task and assembly task,respectively.While significant correlations were found between cortical activation and unimanual tasks,no significant correlations were observed with bimanual tasks.This study provides insights into the neural basis of bimanual coordination and fine motor skills in high-functioning patients after stroke,highlighting task-dependent neural responses.The findings also suggest that patients who exhibit better bimanual performance demonstrate more efficient cortical activation.Therefore,incorporating bilateral arm training in post-stroke rehabilitation is important for better outcomes.The combination of functional near-infrared spectroscopy with functional motor paradigms is valuable for assessing skills and developing targeted interventions in stroke rehabilitation.

Rapid Determination of Hemicellulose Content in Corn Stalks by Near-infrared Spectroscopy Based on Dung Beetle Optimizer

Corn stalks are a kind of common organic fertilizer and feed material in agriculture in China,as well as an important source of modern biomass energy and new materials.Hemicellulose is an important component in corn stalks,and it is very important to determine its content in corn stalks.In this paper,the feasibility of near-infrared spectroscopy(NIRS)combined with chemometrics for rapid detection of hemicellulose content in corn stalks was studied.In order to improve the accuracy of NIRS detection,a new intelligent optimization algorithm,dung beetle optimizer(DBO),was applied to select characteristic wavelengths of NIRS.Its modeling performance was compared with that based on characteristic wavelength selection using genetic algorithm(GA)and binary particle swarm optimization(BPSO),and it was found that the characteristic wavelength selection performance of DBO was excellent,and the regression accuracy of hemicellulose quantitative detection model established by its preferred characteristic wavelengths was better than the above two intelligent optimization algorithms.

Near-infrared cholangiography with intragallbladder indocyanine green injection in minimally invasive cholecystectomy

Laparoscopic cholecystectomy(LC)remains one of the most commonly performed procedures in adult and paediatric populations.Despite the advances made in intraoperative biliary anatomy recognition,iatrogenic bile duct injuries during LC represent a fatal complication and consist an economic burden for healthcare systems.A series of methods have been proposed to prevent bile duct injury,among them the use of indocyanine green(ICG)fluorescence.The most commonly reported method of ICG injection is the intravenous administration,while literature is lacking studies investigating the direct intragallbladder ICG injection.This narrative mini-review aims to assess the potential applications,usefulness,and limitations of intragallbladder ICG fluorescence in LC.Authors screened the available international literature to identify the reports of intragallbladder ICG fluorescence imaging in minimally invasive cholecystectomy,as well as special issues regarding its use.Literature search retrieved four prospective cohort studies,three case-control studies,and one case report.In the three case-control studies selected,intragallbladder near-infrared cholangiography(NIRC)was compared with standard LC under white light,with intravenous administration of ICG for NIRC and with standard intraoperative cholangiography(IOC).In total,133 patients reported in the literature have been administered intragallbladder ICG administration for biliary mapping during LC.Literature includes several reports of intragallbladder ICG administration,but a standardized technique has not been established yet.Published data suggest that NIRC with intragallbladder ICG injection is a promising method to achieve biliary mapping,overwhelming limitations of IOC including intervention and radiation exposure,as well as the high hepatic parenchyma signal and time interval needed in intravenous ICG fluorescence.Evidence-based guidelines on the role of intragallbladder ICG fluorescence in LC require the assessment of further studies and multicenter data collection into large registries.

A New Heptamethine Cyanine-Based Near-Infrared Fluorescent Probe for Divalent Copper Ions with High Selectivity

A new near-infrared fluorophore 2-(2-Aminoethyl) pyridine-tricarbocyanine (1) was rationally designed and synthe-sized as a fluorescent probe for detection of Cu2+ with high selectivity. The response of Probe 1 is based on the fluorescence quenching upon binding to Cu2+. The sensing performance of the proposed Cu2+-sensitive Probe 1 was then investigated. The probe can be applied to the quantification detection of Cu2+ with a linear concentration range covering from 4.8 × 10-7 to 1.6 × 10-4 mol/L and a detection limit of 9.3 × 10-8 mol/L. The experimental results showed that the response of 1 to Cu2+ was independent of pH in medium condition (pH 6.0-8.0), and exhibited excellent selectivity towards Cu2+ over other common metal cations.

Spectrally distinct near-infrared probes for multiplexed biomedical imaging

Our bodies contain a huge amount of anatomical,physiological,cellular or molecular information.The understanding of how these pieces of information are organized has a significant impact on the progress of biology and biomedicine.At present,fluorescence multiplexing approaches,such as immunofluorescence and fluorescence in situ hybridization(FISH).

Suppressing neuroinflammation using the near-infrared light emitted by (Sr,Ba)Ga_(12)O_(19): Cr^(3+) phosphor

Neurodegenerative diseases,such as Parkinson’s and Alzheimer’s diseases,affect the elderly worldwide and will become more prevalent as the global population ages.Neuroinflammation is a common characteristic of neurodegenerative diseases.By regulating the phenotypes of microglia,it is possible to suppress neuroinflammation and,in turn,help prevent neurodegenerative diseases.We report a noninvasive photonic approach to regulating microglia from overexcited M1/M2 to the resting M0 phenotype using a special near-infrared(NIR)light emitted by the SrGa_(12)O_(19)∶Cr^(3t) phosphor.The absorbance and internal and external quantum efficiencies of the optimal SreGa_(0.99)Cr_(0.01)_(12)O_(19) phosphor synthesized at 1400℃ for 8 h using 1%H_(3)BO_(3) t 1%AlF3 as flux are 53.9%,99.2%,and 53.5%;the output power and energyconversion efficiency of the LED device packaged using the optimal SrGa_(12)O_(19): Cr^(3+) phosphor driven at 20 mA reach unprecedentedly 19.69 mW and 37.58%,respectively.The broadband emission of the NIR LED device covers the absorption peaks of cytochrome c oxidase well,and the NIR light can efficiently promote the proliferation of microglia,produce adenosine triphosphate(ATP),reverse overexcitation,alleviate and inhibit inflammation,and improve cell survival rate and activity,showing great prospects for photomedicine application.

A ratiometric near-infrared fluorescent probe for the detection and monitoring of hypochlorous acid in rheumatoid arthritis model and real water samples

Recent studies revealed that the increased level of hypochlorous acid(HOCl)may be deemed to be one of the signs of chronic inflammatory joint disease.Accordingly,the development of effective methods for rapid and accurate detection or monitoring of HOCl in vivo is of great significance for further understanding the role of HOCl in rheumatoid arthritis(RA).Herein,a ratiometric near-infrared(NIR)fluorescent probe(PTA)was reported for the detection and monitoring of HOCl.In the presence of HOCl,the electron-rich S atom and C=C double bond of probe PTA were oxidized in sequence,resulting in the significant hypochromatic shift and decline of absorption spectra.Simultaneously,the intramolecular charge transfer(ICT)process of PTA is inhibited,causing the intrinsic fluorescence emission of PTA shift from 680 to 550 nm.PTA-based test paper strips were successfully prepared and applied to determinate HOCl in actual water samples by“naked eye”colorimetric method.PTA features NIR emission,large Stokes shift(200 nm),low cytotoxicity,high sensitivity(33.9 nM),and short response time(45 s),which enable it to be successfully utilized for imaging endogenous and exogenous HOCl in living zebrafish and mice.More importantly,PTA shows remarkable effectiveness for the monitoring of HOCl-mediated treatment response to RA.Consequently,PTA provides a new approach to further understand the role of HOCl in RA and evaluate the drug treatment efficiency of RA.

Optical Probe for Near-Infrared (NIR) Fluorescence Signal Detection with High Optical Performance and Thermal Stability

We propose a new optical probe for near-infrared (NIR) fluorescence signal detection with high optical performance and thermal stability. The optical probe is composed of an optical source part for efficient excitation of NIR fluorescence signal, a heat dissipation part for stable operation of the NIR fluorescence probe, and an optical detection part for efficient detection of NIR fluorescence signal. From a simulation by use of an optical simulation tool, Light ToolsTM, we could confirm that the optical probe has optical propagation efficiency of 79.6% in case of using a circular detector with 20 cm in diameter located at 20 cm in distance from the optical source. From a measurement of temperature variation of the optical probe, we could also confirm that the optical probe has thermal stability with a standard deviation of 2.19°C under room temperature condition. Finally, from an evaluation of fluorescence image quality, we could confirm that an optical noise which can bring on by overlapped band between optical spectrum of the optical source for fluorescence excitation and optical spectrum of the emitted fluorescence signal decreased effectively in the optical probe.

Methods to Minimize Optical Noise That Degrade Fluorescence Efficiency of Optical Probe for Near-Infrared Tracking in Surgical Environment

In the medical field, there are growing interests in applied research such as in vivo fluorescence monitoring because of excellent body transmission characteristic of the near-infrared light. However, optical noise by excitation light and illumination equipment for medical applications such as interior light, surgical light decrease efficiency of the fluorescent signal when observers such as surgeons confirm fluorescence signals in medical field. To solve these problems in medical field, we have analyzed external noise factors by effect on image realization, quantification of optical noise generation by external factors, and have suggested methods of minimize the optical noise in this paper. In case of fluorescence imaging in the operating room, it has been confirmed that fluorescent excitation light, interior light and surgical light are factors to generate optical noise. To acquire near-infrared fluorescence images and to compare fluorescence contrast under conditions of darkroom, interior light and surgical light, light emitting diodes (LEDs) sources that have peak wavelength at 740, 760 and 780 nm respectively were used as excitation light sources. In addition, short-pass filter which has transmission edge at 775 nm has been applied to minimize the optical noise in each external noise factor. By comparing contrast of each image before and after use of the short-pass filter, we confirmed that optical noise reduced 49%, 56% and 66% in external noise factors respectively.

Conditionally restricted fluorescent probe for Fe^(3+)and Cu^(2+)based on the naphthalimide structure

To address the lack of systematic studies on heavy metal fluorescent probes in typical buffer solutions,this study developed a Fe^(3+)and Cu^(2+)fluorescent probe,DHU‑NP‑4,based on a naphthalimide fluorophore.Comparative analysis of the probe's performance in various buffer systems revealed that buffers with high organic content are unsuitable for evaluating such probes.Furthermore,the pH of the solvent system was found to significantly influence the probe's behavior.Under highly acidic conditions(pH≤2),DHU‑NP‑4 exhibited exceptional specificity for Fe^(3+),while in alkaline conditions,it demonstrated high specificity for Cu^(2+).Leveraging these properties,the probe enabled the quantitative detection of Fe^(3+)and Cu^(2+)in solution.

NONINVASIVE OPTICAL IMAGING OF STAPHYLOCOCCUS AUREUS INFECTION IN VIVO USING AN ANTIMICROBIAL PEPTIDE FRAGMENT BASED NEAR-INFRARED FLUORESCENT PROBES

The diagnosis of bacterial infections remains a major challenge in medicine.Optical imaging of bacterial infection in living animals is usually conducted with genetic reporters such as lightemitting encymes or fluorescent proteins.However,there are many circumstances where genetic reporters are not applicable,and there is an urgent need for exogenous synthetic probes that can selectively target bacteria.Optical imaging of bacteria in vivo is much less developed than methods such as ndioimaging and MRI.Furthermore near infrared(NIR)dyes with emision wavelengths in the region of 650-900 rm can propagate through two or more centimeters of tissue and may enable deeper tisue imaging if sensitive detection techniques are employed.Here we constructed an antimicrobial peptide fragment UBI29-41-based near infrared fuorescent imaging probe.The probe is composed of UBI2941 conjugated to a near infraured dye ICG Der-02.UBI29-41 is a cationic antimicrobial peptide that targets the anionic surfaces of bacterial cells.The probe allows detection of Staphylococcus aureus infection(5×10^(7)cells)in a mouse local infection model using whole animal nearinfrared fuorescence imaging.Furthermore,we demonstrate that the UBI29-41-based imaging probe can selectively accumulate within bacteria.The significantly higher accumulation in bacterial infection suggests that UBI29-41-based imaging probe may be a promising imaging agent to detect bacterial infections.

PREPARATION AND CHARACTERIZATION OF WATER-SOLUBLE NEAR-INFRARED EMITTING PbS QUANTUM DOTS

A new facile method for preparing water-soluble near-infrared （NIR）-emitting PbS quantum dots （QDs） is proposed by using N-acetyl-L-cysteine （NAC, a derivate of L-cysteine） as its stabilizer. The influence of the precursor Pb/S molar ratio, the Pb/NAC molar ratio, and the pH of original solution on optical properties is explored. Results show that aqueous PbS QDs with strong NIR fluorescence can be prepared and their photoluminescence emission peaks can be tuned from 895 nm to 970 nm. Studies indicate that such aqueous QDs have a potential application in biomedical imaging, especially in noninvasive in vivo fluorescence imaging. In addition, the resulting PbS QDs are further characterized by a transmission electron microscopy and X-ray diffraction analysis.