Construction of recombinant Omp25 or EipB protein loaded PLGA nanovaccines for Brucellosis protection.

Safe and effective vaccine candidates are needed to address the limitations of existing vaccines against Brucellosis, a disease responsible for substantial economic losses in livestock. The present study aimed to encapsulate recombinant Omp25 and EipB proteins, knowledged antigen properties, into PLGA nanoparticles, characterize synthesized nanoparticles with different methods, and assessed theirin vitro/in vivoimmunostimulatory activities to develop new vaccine candidates. The recombinant Omp25 and EipB proteins produced with recombinant DNA technology were encapsulated into PLGA nanoparticles by double emulsion solvent evaporation technique. The nanoparticles were characterized using FE-SEM, Zeta-sizer, and FT-IR instruments to determine size, morphology, zeta potentials, and polydispersity index values, as well as to analyze functional groups chemically. Additionally, the release profiles and encapsulation efficiencies were assessed using UV-Vis spectroscopy. After loading with recombinant proteins, O-NPs reached sizes of 221.2 ± 5.21 nm, while E-NPs reached sizes of 274.4 ± 9.51 nm. The cumulative release rates of the antigens, monitored until the end of day 14, were determined to be 90.39% for O-NPs and 56.1% for E-NPs. Following the assessment of thein vitrocytotoxicity and immunostimulatory effects of both proteins and nanoparticles on the J774 murine macrophage cells,in vivoimmunization experiments were conducted using concentrations of 16µg ml-1for each protein. Both free antigens and antigen-containing nanoparticles excessively induced humoral immunity by increasing producedBrucella-specific IgG antibody levels for 3 times in contrast to control. Furthermore, it was also demonstrated that vaccine candidates stimulated Th1-mediated cellular immunity as well since they significantly raised IFN-gamma and IL-12 cytokine levels in murine splenocytes rather than IL-4 following to immunization. Additionally, the vaccine candidates conferred higher than 90% protection from the infection according to challenge results. Our findings reveal that PLGA nanoparticles constructed with the encapsulation of recombinant Omp25 or EipB proteins possess great potential to triggerBrucella-specific humoral and cellular immune response.

RABV antigenic peptide loaded polymeric nanoparticle production, characterization, and preliminary investigation of its biological activity.

Nanoparticle-based antigen carrier systems have become a significant area of research with the advancement of nanotechnology. Biodegradable polymers have emerged as particularly promising carrier vehicles due to their ability to address the limitations of existing vaccine systems. In this study, we successfully encapsulated the G5-24 linear peptide, located between amino acids 253 and 275 in the primary sequence of the rabies virus G protein, into biodegradable and biocompatible PLGA copolymer using the double emulsion solvent evaporation method. The resulting nanoparticles had a size of approximately 230.9 ± 0.9074 nm, with a PDI value of 0.168 ± 0.017 and a zeta potential value of -9.86 ± 0.132 mV. SEM images confirmed that the synthesized nanoparticles were uniform in size and distribution. Additionally, FTIR spectra indicated successful peptide loading into the nanoparticles. The encapsulation efficiency of the peptide-loaded nanoparticles was 73.3%, with a peptide loading capacity of 48.2% and a reaction yield of 30.4%. Peptide release studies demonstrated that 65.55% of the peptide was released in a controlled manner over 28 d, following a 'biphasic burst release' profile consistent with the degradation profile of PLGA. This controlled release is particularly beneficial for vaccine studies. Cytotoxicity tests revealed that the R-NP formulation did not induce cytotoxicity in fibroblast cells and enhanced NO production in macrophages, indicating its potential for vaccine development.

Resuscitation of the Helicobacter pylori Coccoid Forms by Resuscitation Promoter Factor Obtained from Micrococcus Luteus.

Helicobacter pylori is a gram negative, spiral-shaped, and microaerophilic bacteria which can cause life-threatening diseases. It is known that more than 55% of the human population in the world is already infected by this bacterium. The traditional treatment of H. pylori infection consists of a combination of two or more antibiotics. However, H. pylori has evolved to turning its shape from spiral to coccoid form in the presence of antibiotics and this decreases the therapeutic efficacies of conventional antibiotic applications. Resuscitation promoter factor (RPF) is a protein secreted by Micrococcus luteus have significant resuscitation effects on some bacteria especially in the group of viable but non-culturable (VBNC) pathogens. However, there is no study in the literature investigating the resuscitation effects of RPF derived from M. luteus on H. pylori in order to change its form from coccoid to spiral. The purpose of this study is to investigate the resuscitation effect of RPF-containing metabolites isolated from M. luteus on the morphological transformation of H. pylori coccoid forms to spiral forms in order to increase their susceptibilities to antibiotic treatments. Rpf-containing metabolites were primarily obtained from M. luteus culture supernatants. H. pylori was exposed to five different conditions such as prolonged culture, incubation at + 4 °C, incubation at + 22 °C, cultivation in PBS and treatment with kanamycin in order to induce transformations of bacteria to coccoid forms. Induced H.pylori coccoids were characterized by inverted microscope, UV spectrophotometer, SEM imaging, and flow-cytometer. As a result, it was found that the most suitable condition for inducing coccoid forms was cultivation of bacteria with kanamycin. Followingly, different concentrations of RPF-containing metabolites were applied on H. pylori coccoids induced by kanamycin. For the first time in this study, it was determined that the Rpf-containing metabolites obtained from M. luteus demonstrated very high resuscitation effect on kanamycin-induced H. pylori coccoid forms. This new approach for resuscitation of H. pylori coccoids is thought to play an important role in increasing the treatment effectiveness of the conventional antibiotics against the infection.

A nanotechnology based new approach for chemotherapy of Cutaneous Leishmaniasis: TIO2@AG nanoparticles - Nigella sativa oil combinations.

Since toxicity and resistance are the major drawbacks of current antileishmanial drugs, studies have been recently focused on combination therapy in fight against leishmaniasis. Combination therapy generally provides opportunity to decrease toxicity of applied agents and enhance their antimicrobial performance. Moreover, this method can be effective in preventing drug resistance. Highly antileishmanial effects of silver doped titanium dioxide nanoparticles (TiAgNps) and Nigella sativa oil were demonstrated in previous studies. However, toxicity is still an important factor preventing use of these molecules in clinic. By considering high antileishmanial potential of each agent and basic principles of combination therapy, we propose that use of combinations including non-toxic concentrations of TiAgNps and N. sativa oil may compose more effective and safer formulations against Leishmania parasites. Therefore, the main goal of the present study was to investigate antileishmanial effects of non-toxic concentrations of TiAgNps and Nigella sativa oil combinations on promastigote and amastigote-macrophage culture systems and also to develop nanotechnology based new antileishmanial strategies against Cutaneous Leishmaniasis. Numerous parameters such as proliferation, metabolic activity, apoptosis, amastigote-promastigote conversion, infection index analysis and nitric oxide production were used to detect antileishmanial efficacies of combinations. Investigated all parameters demonstrated that TiAgNps-N. sativa oil combinations had significant antileishmanial effect on each life forms of parasites. Tested combinations were found to decrease proliferation rates of Leishmania tropica promastigotes in a range between 1,5-25 folds and metabolic activity values between 2 and 4 folds indicating that combination applications lead to virtually inhibition of promastigotes and elimination of parasites were directly related to apoptosis manner. TiAgNps-N. sativa combinations also demonstrated killing effects on L. tropica amastigotes by decreasing infection index values of macrophages 5-20 folds, inhibiting their metabolic activities up to 5 fold, preventing amastigote-promastigote conversion and producing high amounts of nitric oxide. All these results emphasize high potential of TiAgNps-N. sativa oil combinations as new, safer and effective antileishmanial formulations against Cutaneous Leishmaniasis.

Preparation, characterization and immunological evaluation: canine parvovirus synthetic peptide loaded PLGA nanoparticles.

BACKGROUND: Canine parvovirus 2 (CPV-2) remains a significant worldwide canine pathogen and the most common cause of viral enteritis in dogs. The 1 L15 and 7 L15 peptides overlap each other with QPDGGQPAV residues (7-15 of VP2 capsid protein of CPV) is shown to produce high immune response. PLGA nanoparticles were demonstrated to have special properties such as; controlled antigen release, protection from degradation, elimination of booster-dose and enhancing the cellular uptake by antigen presenting cells. Nevertheless, there is no study available in literature, about developing vaccine based on PLGA nanoparticles with adjuvant properties against CPV. Thus, the aim of the present study was to synthesize and characterize high immunogenic W-1 L19 peptide (from the VP2 capsid protein of CPV) loaded PLGA nanoparticle and to evaluate their in vitro immunogenic activity. RESULTS: PLGA nanoparticles were produced with 5.26 ± 0.05 % loading capacity and high encapsulation efficiency with 81.2 ± 3.1 %. Additionally, it was evaluated that free NPs and W-1 L19 peptide encapsulated PLGA nanoparticles have Z-ave of 183.9 ± 12.1 nm, 221.7 ± 15.8 nm and polydispersity index of 0.107 ± 0.08, 0.135 ± 0.12 respectively. It was determined that peptide loaded PLGA nanoparticles were successfully phagocytized by macrophage cells and increased NO production at 2-folds (*P < 0.05) in contrast to free peptide, and 3-folds (*P < 0.01) in contrast to control. CONCLUSION: In conclusion, for the first time, W-1 L19 peptide loaded PLGA nanoparticles were successfully synthesized and immunogenic properties evaluated. Obtained results showed that PLGA nanoparticles enhanced the capacity of W-1 L19 peptide to induce nitric oxide production in vitro due to its adjuvant properties. Depend on the obtained results, these nanoparticles can be accepted as potential vaccine candidate against Canine Parvovirus. Studies targeting PLGA nanoparticles based delivery system must be maintained in near future in order to develop new and more effective nano-vaccine formulations.

Applications of Exosome Vesicles in Different Cancer Types as Biomarkers.

One of the biggest challenges in the fight against cancer is early detection. Early diagnosis is vital, but there are some barriers such as economic, cultural, and personal factors. Considering the disadvantages of radiological imaging techniques or serological analysis methods used in cancer diagnosis, such as being expensive, requiring expertise, and being time-consuming, there is a need to develop faster, more reliable, and cost-effective diagnostic methods for use in cancer diagnosis. Exosomes, which are responsible for intercellular communication with sizes ranging from 30-120 nm, are naturally produced biological nanoparticles. Thanks to the cargo contents they carry, they are a potential biomarker to be used in the diagnosis of cancer. Exosomes, defined as extracellular vesicles of endosomal origin, are effective in cancer growth, progression, metastasis, and drug resistance, and changes in microenvironmental conditions during tumor development change exosome secretion. Due to their high cellular activity, tumor cells produce much higher exosomes than healthy cells. Therefore, it is known that the number of exosomes in body fluids is significantly rich compared to other cells and can act as a stand-alone diagnostic biomarker. Cancer- derived exosomes have received great attention in recent years for the early detection of cancer and the evaluation of therapeutic response. In this article, the content, properties, and differences of exosomes detected in common types of cancer (lung, liver, pancreas, ovaries, breast, colorectal), which are the leading causes of cancer-related deaths, are reviewed. We also discuss the potential utility of exosome contents as a biomarker for early detection, which is known to be important in targeted cancer therapy.

Combining Killed Vaccine Candidate with Different Adjuvants to Determine Prophylactic Potential against Leishmaniasis.

Visceral Leishmaniasis is a serious public health problem caused by Leishmania species parasites. Approximately 500 thousand people get Visceral Leishmaniasis (VL) every year. An effective and reliable vaccine against the disease has still not been formulated. Choosing the right adjuvant is important to increase immunogenicity in vaccines prepared with total antigens. In this study, we investigate the ideal adjuvant for use in vaccine formulations against VL. For this purpose, Leishmania antigens (FTLA) obtained from L. infantum parasites by the freeze-thaw method and three different adjuvants (alum-saponin and calcium phosphate) were used. The effectiveness of the formulations was investigated in vitro by cell viability analysis and determination of nitric oxide and cytokine production abilities in J774 macrophage cells. According to the study results, it was determined that formulations prepared with calcium phosphate produced 72% more NO and approximately 7.2 times more IL-12 cytokine. The results obtained showed that calcium phosphate salts can be used as ideal adjuvants in vaccine research against leishmaniasis.

Manufacturing Radially Aligned PCL Nanofibers Reinforced With Sulfated Levan and Evaluation of its Biological Activity for Healing Tympanic Membrane Perforations.

The main objective of this study is to construct radially aligned PCL nanofibers reinforced with levan polymer and investigate their in vitro biological activities thoroughly. First Halomonas levan (HL) polysaccharide is hydrolyzed (hHL) and subjected to sulfation to attain Sulfated hydrolyzed Halomonas levan (ShHL)-based material indicating heparin mimetic properties. Then, optimization studies are carried out to produce coaxially generated radially aligned Poly(caprolactone) (PCL) -ShHL nanofibers via electrospinning. The obtained nanofibers are characterized with Fourier Transform Infrared Spectroscopy (FTIR) and Field Emission Scanning Electron Microscopy with Energy Dispersive X-Ray (FESEM-EDX) analysis, and mechanical, contact angle measurement, biodegradability, and swelling tests as well. Afterward, cytotoxicity of artificial tympanic membranes is analyzed by MTT (3-(4,5-Dimethylthiazol-2-yl) -2,5 Diphenyltetrazolium Bromide) test, and their impacts on cell proliferation, cellular adhesion, wound healing processes are explored. Furthermore, an additional FESEM imaging is performed to manifest the interactions between fibroblasts and nanofibers. According to analytical measurements it is detected that PCL-ShHL nanofibers i) are smaller in fiber diameter, ii) are more biodegradable, iii) are more hydrophilic, and iv) demonstrated superior mechanical properties compared to PCL nanofibers. Moreover, it is also deciphered that PCL-ShHL nanofibers strongly elevated cellular adhesion, proliferation, and in vitro wound healing features compared to PCL nanofibers. According to obtained results it is assumed that newly synthetized levan and PCL mediated nanofibers are very encouraging for healing tympanic membrane perforations.

Tannic Acid Incorporated Antibacterial Polyethylene Glycol Based Hydrogel Sponges for Management of Wound Infections.

Conventional wound dressings fail to provide features that can assist the healing process of chronic wounds. Multifunctional wound dressings address this issue by incorporating attributes including antibacterial and antioxidant activity, and the ability to enhance wound healing. Herein, polyethylene glycol (PEG)-based antibacterial hydrogel sponge dressings are prepared by a rapid and facile gas foaming method based on an acid chloride/alcohol reaction where tannic acid (TA) is included as a reactant to impart antibacterial efficacy as well as to enhance the mechanical properties of the samples. The results reveal that the TA-integrated sponges possess excellent antibacterial properties against both Escherichia coli and Staphylococcus aureus with approximately 6-8 log reduction in the microbial colony count after 6 h, indicating their high potential for management of infection-prone wounds. Compared to the control sample, TA incorporation increases the elastic modulus by twofold. As the samples also exhibit biocompatibility, antioxidant activity, and wound healing capacity, the novel TA-incorporated hydrogels can be an alternative to traditional wound dressings for wounds with low-to-moderate exudate.

Investigation of antileishmanial activities of Tio2@Ag nanoparticles on biological properties of L. tropica and L. infantum parasites, in vitro.

Leishmaniasis is a public health problem which is caused by protozoon parasites belonging to Leishmania species. The disease threatens approximately 350 million people in 98 countries all over the world. Cutaneous Leishmaniasis (CL) and Visceral Leishmaniasis (VL) are the mostly commonly seen forms of the disease. Treatment of the disease has remained insufficient since current antileishmanial drugs have several disadvantages such as toxicity, costliness and drug-resistance. Therefore, there is an immediate need to search for new antileishmanial compounds. TiO2@Ag nanoparticles (TiAg-Nps) have been demonstrated as promising antimicrobial agents since they provide inhibition of several types of bacteria. The basic antimicrobial mechanism of TiAg-Nps is the generation of reactive oxygen species (ROS). Even though Leishmania parasites are sensitive to ROS, there is no study in literature indicating antileishmanial activities of TiAg-Nps. Herein, in this study, TiAg-Nps are shown to possess antileishmanial effects on Leishmania tropica and Leishmania infantum parasites by inhibiting their biological properties such as viability, metabolic activity, and survival within host cells both in the dark and under visible light. The results indicate that TiAg-Nps decreased viability values of L. tropica, and L. infantum promastigotes 3- and 10-fold, respectively, in the dark, while these rates diminished approximately 20-fold for each species in the presence of visible light, in contrast to control. On the other hand, non-visible light-exposed TiAg-Nps inhibited survival of amastigotes nearly 2- and 2.5-fold; while visible light-exposed TiAg-Nps inhibited 4- and 4.5-fold for L. tropica and L. infantum parasites, respectively. Consequently, it was determined that non-visible light-exposed TiAg-Nps were more effective against L. infantum parasites while visible light-exposed TiAg-Nps exhibited nearly the same antileishmanial effect against both species. Therefore, we think that a combination of TiAg-Nps and visible light can be further used for treatment of CL, while application of TiAg-Nps alone can be a promising alternative in VL treatment.

The mTOR Signaling Pathway and mTOR Inhibitors in Cancer: Next-generation Inhibitors and Approaches.

mTOR is a serine/threonine kinase that plays various roles in cell growth, proliferation, and metabolism. mTOR signaling in cancer becomes irregular. Therefore, drugs targeting mTOR have been developed. Although mTOR inhibitors rapamycin and rapamycin rapalogs (everolimus, rapamycin, temsirolimus, deforolimus, etc.) and new generation mTOR inhibitors (Rapalink, Dual PI3K/mTOR inhibitors, etc.) are used in cancer treatments, mTOR resistance mechanisms may inhibit the efficacy of these drugs. Therefore, new inhibition approaches are developed. Although these new inhibition approaches have not been widely investigated in cancer treatment, the use of nanoparticles has been evaluated as a new treatment option in a few types of cancer. This review outlines the functions of mTOR in the cancer process, its resistance mechanisms, and the efficiency of mTOR inhibitors in cancer treatment. Furthermore, it discusses the next-generation mTOR inhibitors and inhibition strategies created using nanoparticles. Since mTOR resistance mechanisms prevent the effects of mTOR inhibitors used in cancer treatments, new inhibition strategies should be developed. Inhibition approaches are created using nanoparticles, and one of them offers a promising treatment option with evidence supporting its effectiveness.

Design of a bactericidal hydrogel scaffold containing genipin crosslinked HF-18 peptide.

Wound healing is a process getting affected by internal and external factors and might be interrupted by infections. To overcome infections during wound healing, novel antibacterial agents such as antimicrobial peptides have gained popularity because of the rising antibiotic resistance. Therefore, in this study, a three-dimensional polymeric scaffold was designed for the controlled release of HF-18 peptide, with the contribution of hyaluronic acid, chondroitin sulfate, and chitosan polymers with the crosslinker genipin. The obtained scaffold structure (OPT) was found to have interconnected pores, was pH-responsive and swelled more in acidic conditions (5446.5% at pH: 5.0). It was observed that HF-18-loaded OPT (P-OPT) was able to release HF-18 peptide both in acidic and neutral conditions in a controlled release manner. This study also demonstrated that both OPT and P-OPT were biocompatible and promoted L929 cell attachment and migration. Antimicrobial activity assessments demonstrated that P-OPT was effectively bactericidal on Staphylococcus aureus and methicillin-resistant S. aureus. Moreover, OPT produced a synergistic effect on the antimicrobial activity of HF-18 peptide, as P-OPT showed activity below the reported MIC value. As a result, OPT is considered a promising scaffold as a carrier for HF-18 for wound healing.

Effect of polycation coating on the long-term pulsatile release of antigenic ESAT-61-20 peptide from PLGA nanoparticles.

The development of novel vaccine formulations against tuberculosis is necessary to reduce the number of new cases worldwide. Polymeric nanoparticles offer great potential as antigen delivery and immunostimulant systems for such purposes. In the study, we have encapsulated the antigenic peptide epitope of ESAT-6 protein of M. tuberculosis into PLGA nanoparticles and coated these nanoparticles with the cationic polymer of quaternized poly(4-vinylpyridine) (QPVP) to obtain a positively charged system as a potential nasal vaccine prototype. The produced spherical nanoparticles had hydrodynamic diameters between 180 and 240 nm with a narrow size distribution. The non-coated nanoparticle exhibited a 3-phase in vitro release profile that was completed in more than 4 months. In this release study, 5% of the peptide was released in the first 6 h and the nanoparticle remained silent until the 70th day. Then, an additional 5% of the peptide was released in 45 days. After coating the nanoparticle with QPVP, the release periods and peptide amounts dramatically changed. The antigenic peptide-loaded nanoparticles coated with the polycation stimulated the macrophages in vitro to release more nitric oxide (NO) compared to the free peptide and non-coated nanoparticle, which reveals the immunostimulant activity of the produced nanoparticle systems. The produced non-coated nanoparticles with the prolonged pulsatile release of the antigenic peptide can be used in the development of single injection self-boosting vaccine formulations. By coating these nanoparticles, both the release profile and immunogenicity can be changed.

Wharton Jelly Derived Mesenchymal Stem Cell's Exosomes Demonstrate Significant Antileishmanial and Wound Healing Effects in Combination with Aloe-Emodin: An in Vitro Study.

The aim of the present study was to explore the antileishmanial performance and wound healing effect of exosomes isolated from Wharton Jelly derived mesenchymal stem cells (WJ-MSCs) in combination with aloe-emodin. MSCs obtained from Wharton Jelly were characterized by flow cytometry. Exosomes were isolated from cultivated stem cells by ultacentrifugation method. Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Nanoparticle Tracking Analysis (NTA) and flow cytometry were used for characterization of obtained exosomes. The cytotoxicities of characterized exosomes and aloe-emodin at different concentrations were investigated on L929 and J774 cell lines. Non-toxic concentrations of each agent were combined and their inhibitory efficacies on L.major promastigotes and amastigotes were investigated by different techniques such as MTT, parasite count and measurements of infection index. Finally, wound healing activities of combinations were examined on in vitro artifical wound model and compared with the use of exosomes alone. According to outcome of flow cytometic analysis, vesicles isolated from WJ-MSCs highly expressed the markers such as CD63 special for exosome profile. SEM and NTA results demonstrated that derived exosomes possessed dimensions between 150 to 200 nanometers and elicited the cup-shape specific to exosomes. Combinations including non-toxic dosages of exosomes and aloe-emodin demonstrated superior antileishmanial effectivenesses both on promastigotes and amastigotes in contrast to use of exosome alone since they lead to inhibition of promastigotes and amastigotes for 4 and 10-folds in comparison to control, respectively. Additionally, combinations elicited more rapidly and effective in vitro wound-healing performance in contrast to use of exosome alone. At the end of 24 h incubation application of combinations gave rise to wound closure at a rate of 72 %, while in the control group 52 % of wound area has not been healed, yet. These results reflect that mentioned combination has great potential to be used in treatment of cutaneus leishmaniasis (CL) since they have magnificient capacity to inhibit Leishmania parasites while enhancing wound healing.

Polymeric Approach to Adjuvant System in Antibody Production against Leishmaniasis Based on Hybridoma Technology.

Background: Leishmaniasis is a zoonotic disease, which is one of the serious public health problems in the world. Nowadays, antibody production using hybridoma technology may be a correct approach in terms of sensitivity in the diagnosis of diseases such as leishmaniasis. The aim of this study was investigation of the effectiveness of different adjuvants on polyclonal antibody production against L. tropica based on hybridoma technique. Methods: Accordingly, Freund's adjuvant (1956, M. tuberculosis), as a classic adjuvant in studies, was used comparatively with the non-toxic polymeric based Polyoxidonium adjuvant. All animal immunization procedures were conducted at Bezm-i Alem University Experimental Animal Research Center. The adjuvant response was tested both in the serum sample and in the antibodies produced by the hybridomas. The antibody titers were determined with ELISA. Results: Freund's and Polyoxidonium (PO) group blood titer's increased approximately 5.5 fold compared to control after the 6th and 8th immunization. Hybridomas produced from mice immunized with PO adjuvant induced only antigen-specific antibody response and did not develop an immune response against the adjuvant. Conclusion: Adjuvant selection is very important in terms of the specificity of antibody responses of cells produced in hybridoma technology. Therefore, PO is recommended as a new adjuvant system in this study.

Preparation and Characterization of Graphene-Based 3D Biohybrid Hydrogel Bioink for Peripheral Neuroengineering.

Peripheral neuropathies can occur as a result of axonal damage, and occasionally due to demyelinating diseases. Peripheral nerve damage is a global problem that occurs in 1.5%-5% of emergency patients and may lead to significant job losses. Today, tissue engineering-based approaches, consisting of scaffolds, appropriate cell lines, and biosignals, have become more applicable with the development of three-dimensional (3D) bioprinting technologies. The combination of various hydrogel biomaterials with stem cells, exosomes, or bio-signaling molecules is frequently studied to overcome the existing problems in peripheral nerve regeneration. Accordingly, the production of injectable systems, such as hydrogels, or implantable conduit structures formed by various bioprinting methods has gained importance in peripheral neuro-engineering. Under normal conditions, stem cells are the regenerative cells of the body, and their number and functions do not decrease with time to protect their populations; these are not specialized cells but can differentiate upon appropriate stimulation in response to injury. The stem cell system is under the influence of its microenvironment, called the stem cell niche. In peripheral nerve injuries, especially in neurotmesis, this microenvironment cannot be fully rescued even after surgically binding severed nerve endings together. The composite biomaterials and combined cellular therapies approach increases the functionality and applicability of materials in terms of various properties such as biodegradability, biocompatibility, and processability. Accordingly, this study aims to demonstrate the preparation and use of graphene-based biohybrid hydrogel patterning and to examine the differentiation efficiency of stem cells into nerve cells, which can be an effective solution in nerve regeneration.

Formulating and Characterizing an Exosome-based Dopamine Carrier System.

Exosomes between 40 and 200 nm in size constitute the smallest subgroup of extracellular vesicles. These bioactive vesicles secreted by cells play an active role in intercellular cargo and communication. Exosomes are mostly found in body fluids such as plasma, cerebrospinal fluid, urine, saliva, amniotic fluid, colostrum, breast milk, joint fluid, semen, and pleural acid. Considering the size of exosomes, it is thought that they may play an important role in central nervous system diseases because they can pass through the blood-brain barrier (BBB). Hence, this study aimed to develop an exosome-based nanocarrier system by encapsulating dopamine into exosomes isolated from Wharton's jelly mesenchymal stem cells (WJ-MSCs). Exosomes that passed the characterization process were incubated with dopamine. The dopamine-loaded exosomes were recharacterized at the end of incubation. Dopamine-loaded exosomes were investigated in drug release and cytotoxicity assays. The results showed that dopamine could be successfully encapsulated within the exosomes and that the dopamine-loaded exosomes did not affect fibroblast viability.

Nano-co-delivery of lipophosphoglycan with soluble and autoclaved leishmania antigens into PLGA nanoparticles: Evaluation of in vitro and in vivo immunostimulatory effects against visceral leishmaniasis.

The aim of the present study was to encapsulate lipophosphoglycan molecule (LPG) which is one of the most immunogenic antigens of Leishmania parasites into PLGA nanoparticles with autoclaved or soluble leishmanial antigens, characterize synthetized nanoparticles with different methods and evaluate their in vitro/in vivo immunostimulatory activities to develop new vaccine candidates. PLGA nanoparticles including LPG and autoclaved leishmania antigen (ALA) or soluble leishmania antigen (ALA) were synthetized by double emulsion solvent evaporation method. The synthetized nanoparticles were characterized by SEM and Zeta-sizer instruments for determination of size, zeta potentials and polydispersity index (PDI) values. The antigen release profiles and encapsulation efficiencies were determined by UV-Vis spectroscopy. Griess reaction and ELISA tests were used for measurements of produced nitric oxide (NO) and cytokine levels of macrophages and splenocytes treated with nanoparticles. For determination of protective effects of nanoparticles, parasite reduction in livers and spleens of immunized mice were calculated by LDU values post-infection. According to results, (SLA-LPG) PLGA NPs and (ALA-LPG) PLGA NPs possessed the sizes of 253 and 307 nm respectively. Antigen-loaded nanoparticles elevated the released NO amounts from macrophages for 14 and 18-folds in contrast to control. Furthermore, synthetized nanoparticles significantly triggered macrophages to produce excessive levels of IFN-γ and IL-12 cytokines. Besides it was detected that vaccination of mice with (SLA-LPG) PLGA NPs and (ALA-LPG) PLGA NPs elicited approximately 80% protection from Visceral Leishmaniasis. Furthermore, (SLA-LPG) PLGA NPs and (ALA-LPG) PLGA NPs lead to 10 to 14-folds increase in secreted Th1 cytokine levels from splenocytes than control demonstrating abundantly stimulation of T cell response following to vaccination with nano-vaccine formulations. These results reveal that both (SLA-LPG) PLGA NPs and (ALA-LPG) PLGA NPs have excellent immunostimulatory activities and they are promising nanovaccine formulations for the prevention of leishmaniasis in near future.

Investigation of antileshmanial activities of Cuminum cyminum based green silver nanoparticles on L. tropica promastigotes and amastigotes in vitro.

Leishmaniasis is one of the most important parasitic diseases, which is caused by Leishmania species. Nowadays; although pentavalent antimonials are used as the basic treatment option for Cutaneous Leishmaniasis, high cost, toxicity and resistance of the parasites to the medication over time are some important limitations causing several problems in the treatment. In recent years, the progress in the field of green nanotechnology provides the development of green nanoparticle-based treatment methods for Cutaneous Leishmaniasis. The importance of green nanoparticles has gradually increased due to their special reductive, stabilizing, antioxidant and non-toxic properties. Although there are many studies based on green nanoparticles against Leishmania parasites, we have not found any research about antileishmanial activities of biosynthesized silver nanoparticles (Bio-AgNPs) using Cuminum cyminum L (Cumin) seed extract. Therefore for the first time in this study in vitro antileishmanial effects of Bio-AgNPs prepared from Cumin seed extract were examined on L. tropica promastigote and amastigote forms and their efficacies were compared with chemically synthetized AgNPs. During the experiments, antileishmanial effects of synthetized nanoparticles were determined on both promastigote and amastigote forms of Leishmania parasites by detecting different parameters such as proliferation, infection index and produced nitric oxide (NO) amounts from macrophages. According to the results, it was shown that Bio-AgNPs and AgNPs excessively inhibited L. tropica promastigotes and amastigotes by significantly decreasing proliferation rates of promastigotes and metabolic activities of amastigotes, as well. Moreover, infection index rates of macrophages revealed remarkable anti-amastigote performances of Bio-AgNPs. Besides, Bio-AgNPs stimulated macrophages to release NO to kill Leishmania parasites. Consequently, for the first time, Bio-AgNPs were found to be more effective on both forms of Leishmania parasites than AgNPs. Obtained results indicated high antileishmanial potential of green nanoparticles on L. tropica parasites, causative agents of Cutaneous Leishmaniasis. Thus, obtained results demonstrated that green nanoparticles can lead to the development of new, safer, stable and more effective antileishmanial formulations against Cutaneous Leishmaniasis.

Current Approaches in Treatment of Diabetic Retinopathy and Future Perspectives.

Diabetes mellitus (DM) is a metabolic disease, which is the most common cause of low vision in developing countries and affects almost all systems of the body. In view of the increase in DM prevalence in the world, it would not be a surprise that diabetic retinopathy (DR) and other vascular complications related to diabetes become a serious public health problem. Currently, vascular endothelial growth factor, laser photocoagulation, and intravitreal steroids are the mainstays for DR treatment, but the efficacy of these treatment strategies remains insufficient. Therefore, new treatment modalities for DR have been developed, such as stem cell therapies, extracellular vesicular system, and nanodrug delivery systems. Although there have been several reviews in the literature on the treatment of DR, we have not confronted any review that has the titles of all these topics. With this review, we aim to present the pathophysiology of DR and to review the current and promising new treatment methods based on stem cells, extracellular vesicular system, and nanodrug delivery systems for the future of DR management.