Oligonucleotide-gold nanoparticle networks for detection of Cryptosporidium parvum heat shock protein 70 mRNA

Antibody-modified Gold Nanobiostructures: Advancing Targeted Photodynamic Therapy for Improved Cancer Treatment

Photodynamic therapy (PDT) is an innovative, non-invasive method of treating cancer that uses light-activated photosensitizers to create reactive oxygen species (ROS). However, challenges associated with the limited penetration depth of light and the need for precise control over photosensitizer activation have hindered its clinical translation. Nanomedicine, particularly gold nanobiostructures, offers promising solutions to overcome these limitations. This paper reviews the advancements in PDT and nanomedicine, focusing on applying antibody-modified gold nanobiostructures as multifunctional platforms for enhanced PDT efficacy and improved cancer treatment outcomes. The size, shape, and composition of gold nanobiostructures can significantly influence their PDT efficacy, making synthetic procedures crucial. Functionalizing the surface of gold nanobiostructures with various molecules, such as antibodies or targeting agents, bonding agents, PDT agents, photothermal therapy (PTT) agents, chemo-agents, immunotherapy agents, and imaging agents, allows composition modification. Integrating gold nanobiostructures with PDT holds immense potential for targeted cancer therapy. Antibody-modified gold nanobiostructures, in particular, have gained significant attention due to their tunable plasmonic characteristics, biocompatibility, and surface functionalization capabilities. These multifunctional nanosystems possess unique properties that enhance the efficacy of PDT, including improved light absorption, targeted delivery, and enhanced ROS generation. Passive and active targeting of gold nanobiostructures can enhance their localization near cancer cells, leading to efficient eradication of tumor tissues upon light irradiation. Future research and clinical studies will continue to explore the potential of gold nanobiostructures in PDT for personalized and effective cancer therapy. The synthesis, functionalization, and characterization of gold nanobiostructures, their interaction with light, and their impact on photosensitizers' photophysical and photochemical properties, are important areas of investigation. Strategies to enhance targeting efficiency and the evaluation of gold nanobiostructures in vitro and in vivo studies will further advance their application in PDT. The integrating antibody-modified gold nanobiostructures in PDT represents a promising strategy for targeted cancer therapy. These multifunctional nanosystems possess unique properties that enhance PDT efficacy, including improved light absorption, targeted delivery, and enhanced ROS generation. Continued research and development in this field will contribute to the advancement of personalized and effective cancer treatment approaches.

Gold Nanoparticles: Biosynthesis and Potential of Biomedical Application

Gold nanoparticles (AuNPs) are extremely promising objects for solving a wide range of biomedical problems. The gold nanoparticles production by biological method ("green synthesis") is eco-friendly and allows minimization of the amount of harmful chemical and toxic byproducts. This review is devoted to the AuNPs biosynthesis peculiarities using various living organisms (bacteria, fungi, algae, and plants). The participation of various biomolecules in the AuNPs synthesis and the influence of size, shapes, and capping agents on the functionalities are described. The proposed action mechanisms on target cells are highlighted. The biological activities of "green" AuNPs (antimicrobial, anticancer, antiviral, etc.) and the possibilities of their further biomedical application are also discussed.

A Review on the Synthesis and Functionalization of Gold Nanoparticles as a Drug Delivery Vehicle

Metal nanoparticles are being extensively used in biomedical fields due to their small size-to-volume ratio and extensive thermal stability. Gold nanoparticles (AuNPs) are an obvious choice for biomedical applications due to their amenability of synthesis, stabilization, and functionalization, low toxicity, and ease of detection. In the past few decades, various chemical methods have been used for the synthesis of AuNPs, but recently, newer environment friendly green approaches for the synthesis of AuNPs have gained attention. AuNPs can be conjugated with a number of functionalizing moieties including ligands, therapeutic agents, DNA, amino acids, proteins, peptides, and oligonucleotides. Recently, studies have shown that gold nanoparticles not only infiltrate the blood vessels to reach the site of tumor but also enter inside the organelles, suggesting that they can be employed as effective drug carriers. Moreover, after reaching their target site, gold nanoparticles can release their payload upon an external or internal stimulus. This review focuses on recent advances in various methods of synthesis of AuNPs. In addition, strategies of functionalization and mechanisms of application of AuNPs in drug and bio-macromolecule delivery and release of payloads at target site are comprehensively discussed.

Synthesis of Thiol Derivatives of Biological Active Compounds for Nanotechnology Application

An efficient method of thiol group introduction to the structure of common natural products and synthetic active compounds with recognized biological efficacy such genistein (1), 5,11-dimethyl-5H-indolo[2,3-b]quinolin (2), capecitabine (3), diosgenin (4), tigogenin (5), flumethasone (6), fluticasone propionate (7), ursolic acid methyl ester (8), and β-sitosterol (9) was developed. In most cases, the desired compounds were obtained easily via two-step processes involving esterification reaction employing S-trityl protected thioacetic acid and the corresponding hydoxy-derivative, followed by removal of the trityl-protecting group to obtain the final compounds. The results of our preliminary experiments forced us to change the strategy in the case of genistein (1), and the derivatization of diosgenin (4), tigogenin (5), and capecitabine (3) resulted in obtaining different compounds from those designed. Nevertheless, in all above cases we were able to obtain thiol-containing derivatives of selected biological active compounds. Moreover, a modelling study for the two-step thiolation of genistein and some of its derivatives was accomplished using the density functional theory (B3LP). A hypothesis on a possible reason for the unsuccessful deprotection of the thiolated genistein is also presented based on the semiempirical (PM7) calculations. The developed methodology gives access to new sulphur derivatives, which might find a potential therapeutic benefit.

Early diagnosis of experimental Trichinella spiralis infection by nano-based enzyme-linked immunosorbent assay (nano-based ELISA)

Trichinellosis is a serious foodborne zoonotic disease. It is an important threat to public health all over the world. Although anti-Trichinella IgG detection is the most widely used method for diagnosis of trichinellosis, but there is an obvious window between clinical symptoms and positive serology. Gold nanoparticles (AuNPs) can be conjugated with antibodies affording them promising applications for bio-chemical detection. Herein, AuNPs-based ELISA was evaluated for the first time in the detection of Trichinella spiralis circulating antigen (CAg) for its potential as a diagnostic tool of experimental infection. Swiss Albino mice were orally inoculated with 100 muscle larvae/mouse. Animals were sacrificed 6, 8, 10, 12, 14, 16, 22 and 28 day-post infection (dpi). Blood samples were tested for CAg by both standard ELISA and nano-based ELISA using anti-rabbit polyclonal IgG conjugated with AuNPs. CAg was only detected by nano-based ELISA 6, 8, 10 dpi and by both formats 12-28 dpi. Nano-based assay recorded a statistically significant high sensitivity (58.33%, 91.67%) and accuracy (72.22%, 94.44%) 8 and 10 dpi, respectively in comparison to standard ELISA. Both assays showed high sensitivity and accuracy 12-28 dpi. Thus, nano-based ELISA could be considered as an early sensitive diagnostic method for experimental trichinellosis.

Gold nanoparticles - against parasites and insect vectors

Nanomaterials are currently considered for many biological, biomedical and environmental purposes, due to their outstanding physical and chemical properties. The synthesis of gold nanoparticles (Au NPs) is of high interest for research in parasitology and entomology, since these nanomaterials showed promising applications, ranging from detection techniques to drug development, against a rather wide range of parasites of public health relevance, as well as on insect vectors. Here, I reviewed current knowledge about the bioactivity of Au NPs on selected insect species of public health relevance, including major mosquito vectors, such as Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. The toxicity of Au NPs against helminths was reviewed, covering Schistosoma mansoni trematodes as well as Raillietina cestodes. Furthermore, I summarized the information available on the antiparasitic role of Au NPs in the fight against malaria, leishmaniosis, toxoplasmosis, trypanosomiasis, cryptosporidiosis, and microsporidian parasites affecting human and animals health. Besides, I examined the employ of Au NPs as biomarkers, tools for diagnostics and adjuvants for the induction of transmission blocking immunity in malaria vaccine research. In the final section, major challenges and future outlooks for further research are discussed, with special reference to the pressing need of further knowledge about the effect of Au NPs on other arthropod vectors, such as ticks, tsetse flies, tabanids, sandflies and blackflies, and related ecotoxicology assays.

Current strategies for diagnosis of paracoccidioidomycosis and prospects of methods based on gold nanoparticles

Paracoccidioidomycosis (PCM) is a human systemic granulomatous mycosis caused by thermodimorphic fungi from Paracoccidioides genus. The disease is prevalent in Latin America and triggers a serious clinical condition. Consequently, rapid diagnosis and treatment are crucial to prevent progression of the disease, which can result in death. Currently, there are several established methods for PCM diagnosis. However, many of these tests still present challenges in terms of cost, accessibility and efficiency. In this scenario, gold nanoparticles represent a promising alternative since they have particular optical and electronic properties, which allow its use for biomolecules detection. This review will briefly present techniques available for PCM diagnosis and the perspectives of implementation of gold nanoparticles for diagnosis of this mycosis.

Nanoparticulate mediated transcutaneous immunization: Myth or reality

Transcutaneous immunization (TCI) is a promising route of vaccine delivery through skin due to many well documented advantages. The main obstacle in TCI is the skin's top dead layer i.e. stratum corneum which is difficult to penetrate. Efficiently delivery of antigen to the immune competent cells of epidermis or dermis in TCI might elicit an effective immune response. In this review, skin immunology with a particular focus on potential of immunological active receptors in influencing adaptive immune responses is highlighted. The challenges with TCI and methods to improve it using different adjuvants, chemical and physical approaches, delivery systems, and combination of above methods to further improve immune response following skin application of antigen are elaborately discussed. Nanoparticulate vaccine delivery systems with reference to their applications in TCI are classified according to their chronological development. Conclusively, clinical translations of above methods are also briefly reviewed.

FROM THE CLINICAL EDITOR

Transcutaneous immunization has been investigated by many as a promising route of vaccination. In this comprehensive review article, the authors described and discussed the existing knowledge and difficulties in this approach. Furthermore, ways of improving transcutaneous delivery were also reviewed.

Gold Nanoparticles for DNA/RNA-Based Diagnostics

The remarkable physicochemical properties of gold nanoparticles (AuNPs) have prompted development in exploring biomolecular interactions with AuNPs-containing systems, pursuing biomedical applications in diagnostics. Among these applications, AuNPs have been remarkably useful for the development of DNA/RNA detection and characterization systems for diagnostics, including systems suitable for point of need. Here, emphasis will be on available molecular detection schemes of relevant pathogens and their molecular characterization, genomic sequences associated with medical conditions (including cancer), mutation and polymorphism identification, and the quantification of gene expression.

A promising road with challenges: where are gold nanoparticles in translational research?

Nanoenabled technology holds great potential for health issues and biological research. Among the numerous inorganic nanoparticles that are available today, gold nanoparticles are fully developed as therapeutic and diagnostic agents both in vitro and in vivo due to their physicochemical properties. Owing to this, substantial work has been conducted in terms of developing biosensors for noninvasive and targeted tumor diagnosis and treatment. Some studies have even expanded into clinical trials. This article focuses on the fundamentals and synthesis of gold nanoparticles, as well as the latest, most promising applications in cancer research, such as molecular diagnostics, immunosensors, surface-enhanced Raman spectroscopy and bioimaging. Challenges to their further translational development are also discussed.

Assessment of the viability of Cryptosporidium parvum oocysts with the induction ratio of hsp70 mRNA production in manure

Determining the presence of viable Cryptosporidium parvum oocysts in complex environmental matrices in hygiene control can prevent the contamination of water resources and food with this pathogen. This study assessed the induction ratio of hsp70 mRNA production by heat shock in different oocysts as a marker of viability. Using different procedures for (m)RNA extraction directly from manure and reverse transcription real-time qPCR, this study found slightly increased hsp70 mRNA contents in viable oocysts that were heat shock induced at 45°C for 20 min compared to not induced oocysts (1.6 fold induction in average). Prolonging the heat shock treatment to 2h did not further increase the copy numbers. Heat shock by consecutive stimuli, such as freezing and then heating, did not yield significantly higher copy numbers than the 45°C treatment. There was a certain background level of hsp70 mRNA in viable oocysts that were not exposed to heat shock, indicating a constitutive production of the transcripts in the oocysts. The production of hsp70 mRNA induced by heat shock in oocysts aged for 9 months that exhibited reduced viability was lower than in fresher oocysts (induction ratio<1.2). No production of hsp70 mRNA by heat shock was detected in 12 months old oocysts that were not viable in the excystation test. Oocysts inactivated at 75°C for 30 min were not able to respond to heat shock, and low amount of copies were occasionally measured only in total RNA extracts, but not in mRNA extracts that were purified directly with an oligo (dT)25 based system. The induction ratio of hsp70 mRNA varied according to the viability of the organisms in a sample. Copy numbers of β-tubulin mRNA in viable oocysts were lower than hsp70 mRNA, therefore the latter is more suitable to detect low numbers of oocysts by RT-qPCR.

Gold nanoparticle contrast agents in advanced X-ray imaging technologies

Recently, there has been significant progress in the field of soft- and hard-X-ray imaging for a wide range of applications, both technically and scientifically, via developments in sources, optics and imaging methodologies. While one community is pursuing extensive applications of available X-ray tools, others are investigating improvements in techniques, including new optics, higher spatial resolutions and brighter compact sources. For increased image quality and more exquisite investigation on characteristic biological phenomena, contrast agents have been employed extensively in imaging technologies. Heavy metal nanoparticles are excellent absorbers of X-rays and can offer excellent improvements in medical diagnosis and X-ray imaging. In this context, the role of gold (Au) is important for advanced X-ray imaging applications. Au has a long-history in a wide range of medical applications and exhibits characteristic interactions with X-rays. Therefore, Au can offer a particular advantage as a tracer and a contrast enhancer in X-ray imaging technologies by sensing the variation in X-ray attenuation in a given sample volume. This review summarizes basic understanding on X-ray imaging from device set-up to technologies. Then this review covers recent studies in the development of X-ray imaging techniques utilizing gold nanoparticles (AuNPs) and their relevant applications, including two- and three-dimensional biological imaging, dynamical processes in a living system, single cell-based imaging and quantitative analysis of circulatory systems and so on. In addition to conventional medical applications, various novel research areas have been developed and are expected to be further developed through AuNP-based X-ray imaging technologies.

Amplification-free detection of Cryptosporidium parvum nucleic acids with the use of DNA/RNA-directed gold nanoparticle assemblies

This study describes the development and evaluation of an amplification-free molecular assay for detection of Cryptosporidium parvum oocysts. The assay employed a pair of oligonucleotide-functionalized gold nanoparticle (AuNP) probes that were complementary to adjacent sequences on C. parvum 18s rRNA. Hybridization of the probes to the target RNA resulted in the assembly of AuNPs into target-linked networks, which were detected both visibly and spectroscopically, by a redshift in the wavelength of light scattered by the gold nanoparticles. The limit of detection was between 4 × 10(5) and 4 × 10(6) copies of RNA per microliter reaction mix, when a short synthetic target or full-length in vitro transcribed target was employed. With total nucleic acids purified from C. parvum oocysts spiked into 100-mg stool, as few as 670 oocysts/μl reaction mix were detected. The ability to detect the nucleic acids of C. parvum oocysts in stool, without the need for complex amplification, offers unique advantages for such AuNP aggregation assays to be extended toward use in resource-limited settings where protozoan detection is needed most.

In vivo imaging of induction of heat-shock protein-70 gene expression with fluorescence reflectance imaging and intravital confocal microscopy following brain ischaemia in reporter mice

PURPOSE

Stroke induces strong expression of the 72-kDa heat-shock protein (HSP-70) in the ischaemic brain, and neuronal expression of HSP-70 is associated with the ischaemic penumbra. The aim of this study was to image induction of Hsp-70 gene expression in vivo after brain ischaemia using reporter mice.

METHODS

A genomic DNA sequence of the Hspa1b promoter was used to generate an Hsp70-mPlum far-red fluorescence reporter vector. The construct was tested in cellular systems (NIH3T3 mouse fibroblast cell line) by transient transfection and examining mPlum and Hsp-70 induction under a challenge. After construct validation, mPlum transgenic mice were generated. Focal brain ischaemia was induced by transient intraluminal occlusion of the middle cerebral artery and the mice were imaged in vivo with fluorescence reflectance imaging (FRI) with an intact skull, and with confocal microscopy after opening a cranial window.

RESULTS

Cells transfected with the Hsp70-mPlum construct showed mPlum fluorescence after stimulation. One day after induction of ischaemia, reporter mice showed a FRI signal located in the HSP-70-positive zone within the ipsilateral hemisphere, as validated by immunohistochemistry. Live confocal microscopy allowed brain tissue to be visualized at the cellular level. mPlum fluorescence was observed in vivo in the ipsilateral cortex 1 day after induction of ischaemia in neurons, where it is compatible with penumbra and neuronal viability, and in blood vessels in the core of the infarction.

CONCLUSION

This study showed in vivo induction of Hsp-70 gene expression in ischaemic brain using reporter mice. The fluorescence signal showed in vivo the induction of Hsp-70 in penumbra neurons and in the vasculature within the ischaemic core.

Miniaturized technology for protein and nucleic acid point-of-care testing

The field of point-of-care (POC) testing technology is developing quickly and producing instruments that are increasingly reliable, while their size is being gradually reduced. Proteins are a common target for POC analyses and the detection of protein markers typically involves immunoassays aimed at detecting different groups of proteins such as tumor markers, inflammation proteins, and cardiac markers; but other techniques can also be used to analyze plasma proteins. In the case of nucleic acids, hybridization and amplification strategies can be used to record electromagnetic or electric signals. These techniques allow for the identification of specific viral or bacterial infections as well as specific cancers. In this review, we consider some of the latest advances in the analysis of specific nucleic acid and protein biomarkers, taking into account their trend toward miniaturization and paying special attention to the technology that can be implemented in future applications, such as lab-on-a-chip instruments.

Gold nanoparticles with asymmetric polymerase chain reaction for colorimetric detection of DNA sequence

We developed a novel strategy for rapid colorimetric analysis of a specific DNA sequence by combining gold nanoparticles (AuNPs) with an asymmetric polymerase chain reaction (As-PCR). In the presence of the correct DNA template, the bound oligonucleotides on the surface of AuNPs selectively hybridized to form complementary sequences of single-stranded DNA (ssDNA) target generated from As-PCR. DNA hybridization resulted in self-assembly and aggregation of AuNPs, and a concomitant color change from ruby red to blue-purple occurred. This approach is simpler than previous methods, as it requires a simple mixture of the asymmetric PCR product with gold colloid conjugates. Thus, it is a convenient colorimetric method for specific nucleic acid sequence analysis with high specificity and sensitivity. Most importantly, the marked color change occurs at a picogram detection level after standing for several minutes at room temperature. Linear amplification minimizes the potential risk of PCR product cross-contamination. The efficiency to detect Bacillus anthracis in clinical samples clearly indicates the practical applicability of this approach.

Functionalized Gold Nanoparticles and Their Biomedical Applications

Metal nanoparticles are being extensively used in various biomedical applications due to their small size to volume ratio and extensive thermal stability. Gold nanoparticles (GNPs) are an obvious choice due to their amenability of synthesis and functionalization, less toxicity and ease of detection. The present review focuses on various methods of functionalization of GNPs and their applications in biomedical research. Functionalization facilitates targeted delivery of these nanoparticles to various cell types, bioimaging, gene delivery, drug delivery and other therapeutic and diagnostic applications. This review is an amalgamation of recent advances in the field of functionalization of gold nanoparticles and their potential applications in the field of medicine and biology.

Newer diagnostic approaches to intestinal protozoa

PURPOSE OF REVIEW

To update the reader on the latest developments in the laboratory diagnosis of intestinal protozoa.

RECENT FINDINGS

Correct identification of a diarrhoea causing pathogens is essential for the choice of treatment in an individual patient as well as to map the aetiology of diarrhoea in a variety of patient populations. Classical diagnosis of diarrhoea causing protozoa by microscopic examination of a stool sample lacks both sensitivity and specificity. Alternative diagnostic platforms are discussed.

SUMMARY

Recent literature on the diagnosis of intestinal protozoa has focused mainly on nucleic acid-based assays, in particular the specific detection of parasite DNA in stool samples using real-time PCR. In addition, the trend has been moving from single pathogen detection to a multiplex approach, allowing simultaneous identification of multiple parasites. Different combinations of targets can be used within a routine diagnostic setting, depending on the patient population, such as children, immunocompromised individuals and those who have been travelling to tropical regions. Large-scale monitoring and evaluation of control strategies become feasible due to automation and high-throughput facilities. Improved technology also has become available for differentiating protozoa subspecies, which facilitates outbreak investigations and extensive research in molecular epidemiology.

Treatment of cryptosporidiosis: do we know what we think we know?

PURPOSE OF REVIEW

The management of cryptosporidiosis is fraught with controversies. New research on diagnostics and medications has reached the field in recent years. Therefore, familiarity with key features of current management tools is important. We discuss diagnostic and therapeutic aspects of cryptosporidiosis focusing on evidence behind the medications available to date.

RECENT FINDINGS

Molecular methods provide a clearer understanding of cryptosporidiosis epidemiology. The major determinants of severity still are host immune status and parasite species. Children and immunosuppressed individuals, especially with HIV/AIDS, are disproportionately affected. Nitazoxanide is an important advance in treatment of HIV negative patients. However, recent research confirms the limited effectiveness of antiparasitic drugs to treat cryptosporidiosis in AIDS. Questions remain about using partially active drugs paromomycin and nitazoxanide for treatment. Potent antiretroviral combinations modify disease epidemiology and are key components of therapy in AIDS. However, it is unclear whether this is due solely to immune reconstitution or due in part to antiparasitic effects of HIV protease inhibitors. Newer candidate drugs are in development.

SUMMARY

There is better understanding of the epidemiology of cryptosporidiosis and promising new diagnostic methods. There are significant challenges in terms of control and treatment of cryptosporidiosis among the groups at risk.