Pharmaceutical Nanotechnology - Volume 8, Issue 5, 2020

As a natural biomaterial, silk fibroin (SF) holds great potential in biomedical applications with its broad availability, good biocompatibility, high mechanical strength, ease of fabrication, and controlled degradation. With emerging fabrication methods, nanoand microspheres made from SF have brought about unique opportunities in drug delivery, cell culture, and tissue engineering. For these applications, the size and distribution of silk fibroin particles (SFPs) are critical and require precise control during fabrication. Herein, we review common and emerging SFPs fabrication methods and their biomedical applications, and also the challenges and opportunities for SFPs in the near future. Lay Summary: The application of silk in textile has an extraordinarily long history and new biomedical applications emerged owing to the good biocompatibility and versatile fabrication options of its major protein component, silk fibroin. With the development of nanotechnology and microfabrication, silk fibroin has been fabricated into nano- or microspheres with precisely controlled shape and distribution. In this review, we summarize common and emerging silk fibroin particle fabrication methods and their biomedical applications, and also discuss their challenges and opportunities in the nearest future.

The deep fungal infection poses serious threats to human health, mainly due to the increase in the number of immunocompromised individuals. Current first-line antifungal agents such as Amphotericin B, Fluconazole and Itraconazole, may decrease the severity of fungal infection to some extent, but the poor drug bioavailability, drug toxicity and poor water solubility seriously restrict their clinical utility. This review focuses on the study of drug delivery strategies for the treatment of deep fungal infections. We summarize the drug delivery strategies recently reported for the treatment of deep fungal infection, and explain each part with research examples. We discuss the use of pharmaceutical approaches to improve the physicochemical properties of the antifungal drugs to provide a basis for the clinical application of antifungal drugs. We then highlight the strategies for targeting drug delivery to the infection sites of fungi and fungal surface moieties, which have the potential to get developed as clinically relevant targeted therapies against deep fungal infections. It is worth noting that the current research on fungal infections still lags behind the research on other pathogens, and the drug delivery strategy for the treatment of deep fungal infections is far from meeting the treatment needs. Therefore, we envision the potential strategies inspired by the treatment of diseases with referential pathology or pathophysiology, further enriching the delivery of antifungal agents, providing references for basic research of fungal infections. Lay Summary: The deep fungal infections pose serious threats to the health of immunodeficiency patients. It is worth noting that the current research on fungi is still lagging behind that on other pathogens. The drug delivery strategies for the treatment of deep fungal infections are far from meeting the treatment needs. We summarize the recently reported drug delivery strategies for treating deep fungal infection, and envision the potential strategies to further enrich the delivery of antifungal agents.

Background: Doxorubicin (DOX) is a leading chemotherapeutic in cancer treatment because of its high potency and broad spectrum. Liposomal doxorubicin (Doxil®) is the first FDA-approved PEG-liposomes of DOX for the treatment of over 600,000 cancer patients, and it can overcome doxorubicin-induced cardiomyopathy and other side effects and prolong life span. The addition of MPEG2000-DSPE could elevate the total cost of cancer treatment. Objective: We intended to prepare a novel DOX liposome that was prepared with inexpensive materials egg yolk lecithin and Kolliphor HS15, thus allowing it to be much cheaper for clinical application. Methods: DOX liposomes were prepared using the combination of thin-film dispersion ultrasonic method and ammonium sulfate gradient method and the factors that influenced formulation quality were optimized. After formulation, particle size, entrapment efficiency, drug loading, stability, and pharmacokinetics were determined. Results: DOX liposomes were near-spherical morphology with the average size of 90 nm and polydispersity index (PDI) of less than 0.30. The drug loading was up to 7.5%, and the entrapment efficiency was over 80%. The pharmacokinetic studies showed that free DOX could be easily removed and the blood concentration of free DOX group was significantly lower than that of DOX liposomes, which indicated that the novel DOX liposome had a certain sustainedrelease effect. Conclusion: In summary, DOX liposome is economical and easy-prepared with prolonged circulation time. Lay Summary: Doxorubicin (DOX) is a leading chemotherapeutic in cancer treatment because of its high potency and broad spectrum. Liposomal doxorubicin (Doxil®) is the first FDAapproved PEG-liposomes of DOX to treat over 600.000 cancer patients, overcoming doxorubicin- induced cardiomyopathy and other side effects and prolonging life span. The addition of MPEG2000-DSPE could elevate the total cost of cancer treatment. We intend to prepare a novel DOX liposome prepared with inexpensive materials egg yolk lecithin and Kolliphor HS15, thus allowing it to be much cheaper for clinical use. The novel DOX liposome is economical and easy-prepared with prolonged circulation time.

Background: Cationic liposomes (CLs) based messenger RNA (mRNA) vaccine has been a promising approach for cancer treatment. However, rapid lung accumulation after intraveous injection and significantly decreased transfection efficacy (TE) in serum substantially hamper its application. Objective: In this study, we attempt to investigate the fate of Mannose-PEG1000-lipoplex (MP1000-LPX) in vivo, a previous reported mRNA vaccine, and potential mechanism in it. Methods: MP1000-CLs and different type of MP1000-LPX were produced by previous method and characterized by dynamic light scattering (DLS). Organ distribution and Luc-mRNA expression of DiD loaded luciferase (Luc-mRNA)-MP1000-LPX were evaluated by IVIS Spectrum imaging system. Cellular transfection and uptake under serum-free and serum-containing conditions were analysed by flow cytometry and counted by FlowJo software. Results: MP1000-CLs had an average size of 45.3 ± 0.9 nm, a positive charge of 39.9 ± 0.9 mV. When MP1000-LPX formed, the particle size increased to about 130 nm, and zeta potential decreased to about 30 mV. All formulations were in narrow size distribution with PDI < 0.3. 6 h after intraveous injection, Luc-MP1000-LPX mostly distributed to liver, lung and spleen, while only successfully expressed Luc in lung. DC2.4 cellular transfection assay indicated serum substantially lowered TE of MP1000-LPX. However, the cellular uptake on DC2.4 cells was enhanced in the presence of serum. Conclusion: MP1000-LPX distributed to spleen but failed to transfect. Because serum dramatically decreased TE of MP1000-LPX on DC2.4 cells, but not by impeding its interaction to cell membrane. Serum resistance and avoidance of lung accumulation might be prerequisites for CLs based intravenous mRNA vaccines. Lay Summary: mRNA vaccine has been promising immunotherapy to treat cancer by delivering mRNA encoding tumor antigens to APCs and activating immune system against tumor cells. We are investigating the in vivo fate of MP1000-LPX, a CLs based mRNA vaccine. To see if serum causes the fate, we’ll be looking at the influence of serum on transfection and uptake efficacy of MP1000-LPX by DC2.4 cells experiments in vitro. Our findings will imply that serum inhibits transfection but not by decreasing uptake. Thus, we can ultilize serum to enhance transfection if we make intracellular process of MP1000-LPX successful.

Background: A key challenge in the process of virus amplification is the need for a simple and convenient method for measuring virus titers. Objective: Real-time unlabeled cell analysis (RTCA) was used to establish a standard curve of correlation between half-cell index time (CIT50) and virus titer. At the same time, the virus titer from tunable resistance pulse detection (TRPS) technology was compared with the traditional median tissue culture infectious dose (TCID50) method to evaluate the feasibility and application value of the RTCA technique and TRPS technology. Methods: Cell index (CI) values for L929 cells under different culture conditions were detected, and the appropriate initial cell inoculation density was screened. The half-cell index (CI50) values of reovirus infected L929 cells with TCID50 titers were analyzed by RTCA, the CI50-TCID50 standard curve was created, and a regression equation was developed. RTCA, TCID50, and TRPS methods were used to detect the reovirus titer obtained by the amplification, and the sensitivity and feasibility of the CIT50-TCID50 standard curve method were analyzed. The virus titer was detected by TRPS technology and the TCID50 method. Results: L929 cells were best propagated at an initial density of 6 x 103 cells/well. After infecting L929 cells with different titers of reference reovirus, the linear correlation of CIT50 and TCID50 was y = -2.1806x + 71.023 (R2 = 0.9742). The titer resulting from the RTCA assay was 7x109.6821 pfu/mL, from the TRPS assay was 4.52x1010 pfu/mL, and from the TCID50 assay was 7x109.467 pfu/mL. Conclusion: The CIT50-TCID50 standard curve method established by the RTCA technique can be used to quantitatively detect reovirus titer with L929 cells. Compared with the TCID50 method, it takes a relatively short time and has high sensitivity and accuracy. The TRPS technology requires even less time to quantify the virus, but its precision is lower than that of the TCID50 method and RTCA technology. This study provides new technical methods for assessing the virulence of infectious live reovirus particles. Lay Summary: After amplification of the virus, we need to detect the virus titers (the virulence of the virus). The traditional method is to use the virus to infect cells, and then the virus titers can be calculated by 50% of the cells infected. However, this traditional method is time consuming. The ways of RTCA (a real-time cell analysis technique) and TRPS (a nano-bioparticle analysis technique) help us to detect viral titers. The consistency of these three methods determines their feasibility and accuracy. If they are feasible, then these two simple technologies will provide new ideas for detecting viral titers.

Background: Antimalarial therapy remains the utmost effective means for the management of malarial parasites in the liver and red blood cells. The application of these therapeutic agents is hampered by their improper application, hepato-toxicity caused by their continuous use, and degradation by hepatic enzymes. Methods: Recent advancements in drug delivery applications have shown potential in improving the pharmacological properties of artemether. Nanostructured lipid carriers (NLCs) loaded chitosan (CH)/Carbopol (CB) hybrid gel was prepared using glycerol monostearate (GMS) as solid lipid and clove oil as a liquid lipid for artemether (ART) and curcumin (CR) for its localized effect on the liver. Results: The smaller particle size (~118 ± 1.0 nm) and high zeta potential (- 41.1 ± 6.46 mV) confirm the formulation and stability of NLCs. On the other hand, the shape and morphology of prepared NLCs and gel showed a spherical and wrinkled surface with a size range of 150-250 nm. The release studies of the NLC’s showed a controlled release of artemether (~ 92%) and curcumin (~ 83%) for up to 30 h. Photostability data showed that, approximately, ~86.5 ± 0.3% and ~60 ± 0.9% of nanoencapsulated artemether and curcumin were still detected on exposure to sunlight, respectively. It has been found from the permeation study that 69.8% and 49.1% of the drug was permeated across the mucus membrane in 24 h with a significant increase (P < 0.05) in flux as well as permeability coefficients. Conclusion: The overall results showed that prepared CH/CB/NLCs hybrid gel could be a promising vehicle for the effective delivery of ART and CR for the management of malarial parasites. Lay Summary: Antimalarial therapy remains the utmost effective means for the management of malarial parasites in liver and red blood cells. Recent advancements in drug delivery applications have shown potential in improving the pharmacological properties of artemether. Application of these therapeutic agents hampered by their improper application, hepato-toxicity caused by their continuous use and degradation by hepatic enzymes. To manage the above issues, we synthesize nanostructured lipid carriers (NLC’s) loaded chitosan (CH)/Carbopol (CB) hybrid gel using glycerol monostearate (GMS) as solid lipid and clove oil as liquid lipid for artemether (ATR) and curcumin (CR) for its local action in liver and the major criteria were to find a protective barrier with hepatoprotective nature of the curcumin.