Formulation design, preparation and characterization of multifunctional alginate stabilized nanodroplets

Chitosan/Alginate-Based Nanoparticles for Antibacterial Agents Delivery

Nanoparticle systems integrating alginate and chitosan emerge as a promising avenue to tackle challenges in leveraging the potency of pharmacological active agents. Owing to their intrinsic properties as polysaccharides, alginate and chitosan, exhibit remarkable biocompatibility, rendering them conducive to bodily integration. By downsizing drug particles to the nano-scale, the system enhances drug solubility in aqueous environments by augmenting surface area. Additionally, the system orchestrates extended drug release kinetics, aligning well with the exigencies of chronic drug release requisite for antibacterial therapeutics. A thorough scrutiny of existing literature underscores a wealth of evidence supporting the utilization of the alginate-chitosan nanoparticle system for antibacterial agent delivery. Literature reviews present abundant evidence of the utilization of nanoparticle systems based on a combination of alginate and chitosan for antibacterial agent delivery. Various experiments demonstrate enhanced antibacterial efficacy, including an increase in the inhibitory zone diameter, improvement in the minimum inhibitory concentration, and an enhancement in the bacterial reduction rate. This enhancement in efficacy occurs due to mechanisms involving increased solubility resulting from particle size reduction, prolonged release effects, and enhanced selectivity towards bacterial cell walls, stemming from ionic interactions between positively charged particles and teichoic acid on bacterial cell walls. However, clinical studies remain limited, and there are currently no marketed antibacterial drugs utilizing this system. Hence, expediting clinical efficacy validation is crucial to maximize its benefits promptly.

Characterising the chemical and physical properties of phase-change nanodroplets

Phase-change nanodroplets have attracted increasing interest in recent years as ultrasound theranostic nanoparticles. They are smaller compared to microbubbles and they may distribute better in tissues (e.g. in tumours). They are composed of a stabilising shell and a perfluorocarbon core. Nanodroplets can vaporise into echogenic microbubbles forming cavitation nuclei when exposed to ultrasound. Their perfluorocarbon core phase-change is responsible for the acoustic droplet vaporisation. However, methods to quantify the perfluorocarbon core in nanodroplets are lacking. This is an important feature that can help explain nanodroplet phase change characteristics. In this study, we fabricated nanodroplets using lipids shell and perfluorocarbons. To assess the amount of perfluorocarbon in the core we used two methods, 19F NMR and FTIR. To assess the cavitation after vaporisation we used an ultrasound transducer (1.1 MHz) and a high-speed camera. The 19F NMR based method showed that the fluorine signal correlated accurately with the perfluorocarbon concentration. Using this correlation, we were able to quantify the perfluorocarbon core of nanodroplets. This method was used to assess the content of the perfluorocarbon of the nanodroplets in solutions over time. It was found that perfluoropentane nanodroplets lost their content faster and at higher ratio compared to perfluorohexane nanodroplets. The high-speed imaging indicates that the nanodroplets generate cavitation comparable to that from commercial contrast agent microbubbles. Nanodroplet characterisation should include perfluorocarbon concentration assessment as critical information for their development.

Ultrasound-guided chemoradiotherapy of breast cancer using smart methotrexate-loaded perfluorohexane nanodroplets

Chemoradiotherapy with controlled-release nanocarriers such as sono-sensitive nanodroplets (NDs) can enhance the anticancer activity of chemotherapy medicines and reduces normal tissue side effects. In this study, folic acid-functionalized methotrexate-loaded perfluorohexane NDs with alginate shell (FA-MTX/PFH@alginate NDs) were synthesized, characterized, and their potential for ultrasound-guided chemoradiotherapy of breast cancer was investigated in vitro and in vivo. The cancer cell (4T1) viabilities and surviving fractions after NDs and ultrasound treatments were significantly decreased. However, this reduction was much more significant for ultrasound in combination with X-ray irradiation. The in vitro and in vivo results confirmed that MTX-loaded NDs are highly biocompatible and they have no significant hemolytic activity and organ toxicity. Furthermore, the in vivo results indicated that the FA-MTX/PFH@alginate NDs were accumulated selectively in the tumor region. In conclusion, FA-functionalized MTX/PFH@alginate NDs have a great theranostic performance for ultrasound-controlled drug delivery in combination with radiotherapy of breast cancer.

GRP78-targeted and doxorubicin-loaded nanodroplets combined with ultrasound: a potential novel theranostics for castration-resistant prostate cancer

The construction of multifunctional oncotherapy nanoplatforms that combine diagnosis and treatment remains challenging. Nanodroplets (NDs), which simultaneously enhance ultrasound imaging and therapeutic effects, are a potential strategy for non-invasive drug delivery. To achieve the goals of precise medicine, novel SP94 peptide-modified and doxorubicin-loaded ultrasonic NDs (SP94-DOX-NDs) for castration-resistant prostate cancer (CRPC) targeting and treatment were constructed in this study. The characteristics, contrast-enhanced ultrasound imaging (CEUI), targeting ability to glucose-regulated protein 78 (GRP78)-overexpressing CRPC and anticancer effect of the SP94-DOX-NDs were assessed. The desired SP94-NDs were successfully prepared using the nanoemulsification method using a certain proportion of SP94-PEG-chitosan, perfluoropentane (PFP), Tween 20, and lecithin. SP94-NDs with a size of ∼300 nm showed great biocompatibility and CEUI ability. Compared with blank NDs, SP94-NDs exhibited higher tumor-specific targeting ability due to conjugation between the SP94 peptide and GRP78-overexpressing 22RV1 cells. Most importantly, in vitro and in vivo investigations showed that SP94-DOX-NDs combined with ultrasound could specifically deliver DOX into 22RV1 cells and thereby demonstrated a stronger anticancer effect than DOX-NDs and DOX. Thus, SP94-DOX-NDs may provide an efficient approach for the real-time imaging of tumors and triggered, accurate drug delivery to tumors.

A comprehensive review on alginate-based delivery systems for the delivery of chemotherapeutic agent: Doxorubicin

Doxorubicin (DOX), an anthracycline drug, is widely used for the treatment of several cancers like osteosarcoma, cervical carcinoma, breast cancer, etc. DOX lacks target specificity; thereby it also affects normal cells thus resulting in several side-effects. A drug delivery system (DDS) can be used to deliver the drug in a controlled and sustained manner at a targeted site within the body. Various DDS like nanoemulsions, polymeric nanoparticles, and liposomes are used for loading DOX. Alginate, a polysaccharide is widely used for fabricating DDS due to its biodegradable and bio-compatible properties. Alginates, in combination with other biomaterials, have been extensively used as a novel drug delivery carrier for DOX. Alginate provides a platform for drug delivery in different forms like hydrogels, nanogels, nanoparticles, microparticles, graphene oxide systems, magnetic systems, etc. Herein, we briefly describe alginate in combination with other materials as a nanocarrier for targeted delivery of DOX for anti-cancer treatment.

Echogenic, Ultrasound-Sensitive Chitosan Nanodroplets for Spatiotemporally Controlled DKK-2 Gene Delivery to Prostate Cancer Cells

Purpose

To synthesize echogenic chitosan/perfluorohexane nanodroplets (CNDs) for DKK-2 gene delivering in a spatiotemporally controlled manner in vitro.

Methods

The characteristics, contrast-enhanced ultrasound imaging, DNA binding and DNase protection capacity, DKK-2 gene transfection and effects on LNCaP cells of these CNDs were investigated.

Results

The obtained CNDs showed positive surface charges and could attract the genetic cargo with negative surface charges to form nanocomplexes. Agarose gel electrophoresis confirmed binding of the CNDs and pDNA. DKK-2 pDNA-loaded CNDs, in combination with ultrasound, ruptured and released DKK-2 pDNA, entering LNCaP cells through nano-scale pores in the cell membrane, which further reduced the proliferation of LNCaP cells.

Conclusion

These stable and safe CNDs may be a promising choice to achieve efficient ultrasound-mediated gene delivery to specific tissues in a spatiotemporally controlled manner.

Ultrasound-responsive highly biocompatible nanodroplets loaded with doxorubicin for tumor imaging and treatment in vivo

As an injectable anticancer drug delivery system, the biological safety of nanocarriers is the most important prerequisite for their clinical application. The objective of our study was to synthesize special ultrasound-responsive highly biocompatible chitosan nanodroplets (BCNDs), observe their spatiotemporally control the delivery of doxorubicin (DOX) in vivo. The experimental results showed that the BCNDs were successfully prepared with high biosafety in vivo and great ultrasound imaging ability. DOX-BCNDs promoted the anticancer effects of DOX in vivo and inhibited the development of tumors. They also reduced the side effects to the heart and kidneys. In conclusion, BCNDs are a new type of smart nanocarrier with high biocompatibility and efficacy have great potential to be used in the clinic.

Alginate Nanoformulation: Influence of Process and Selected Variables

Nanocarriers are defined as structures and devices that are constructed using nanomaterials which add functionality to the encapsulants. Being small in size and having a customized surface, improved solubility and multi-functionality, it is envisaged that nanoparticles will continue to create new biomedical applications owing to their stability, solubility, and bioavailability, as well as controlled release of drugs. The type and physiochemical as well as morphological attributes of nanoparticles influence their interaction with living cells and determine the route of administration, clearance, as well as related toxic effects. Over the past decades, biodegradable polymers such as polysaccharides have drowned a great deal of attention in pharmaceutical industry with respect to designing of drug delivery systems. On this note, biodegradable polymeric nanocarrier is deemed to control the release of the drug, stabilize labile molecules from degradation and site-specific drug targeting, with the main aim of reducing the dosing frequency and prolonging the therapeutic outcomes. Thus, it is essential to select the appropriate biopolymer material, e.g., sodium alginate to formulate nanoparticles for controlled drug delivery. Alginate has attracted considerable interest in pharmaceutical and biomedical applications as a matrix material of nanocarriers due to its inherent biological properties, including good biocompatibility and biodegradability. Various techniques have been adopted to synthesize alginate nanoparticles in order to introduce more rational, coherent, efficient and cost-effective properties. This review highlights the most used and recent manufacturing techniques of alginate-based nanoparticulate delivery system, including emulsification/gelation complexation, layer-by-layer, spray drying, electrospray and electrospinning methods. Besides, the effects of the main processing and formulation parameters on alginate nanoparticles are also summarized.

The effect of dual-frequency ultrasound waves on B16F10 melanoma cells: Sonodynamic therapy using nanoliposomes containing methylene blue

BACKGROUND

We investigated the effect of dual-frequency sonication on the viability of B16F10 melanoma cells in the presence of methylene blue (MB) encapsulated in nanoliposomes.

METHODS

Treatment protocols were studied: sonication groups (40 kHz, 1 MHz and dual-frequency), the same sonication groups with nanoliposomes containing MB, MB free and nanoliposomes containing MB groups, and so sham and control groups. The nanoliposomes were prepared by the lipid film hydration method. The cell viability of the different treatment groups was evaluated by the MTT assay.

RESULTS

The dual-frequency protocols caused higher viability losses compared to the kHz and MHz sonications (P < .05). In presence of the nanoliposomes containing MB, dual frequency led to 6% and 3% viability for 600 and 1200 seconds, respectively, while the corresponding values were 10% and 4% for the 40 kHz protocols and 22% and 9% for the 1 MHz, as compared to the control group (100%). The result of KI dosimetry showed that the cavitation activity of the dual-frequency protocol was about 1.23, as compared to sonication at 40 kHz and 1 MHz.

CONCLUSION

Enhancement of inertial cavitation induction by dual-frequency sonication may be the primary effective mechanism, which causes increased sonochemical processes and drug release from nanocarriers.

Charge-conversion and ultrasound-responsive O-carboxymethyl chitosan nanodroplets for controlled drug delivery

Aim: O-carboxymethyl chitosan/perfluorohexane nanodroplets (O-CS NDs) and doxorubicin-loading O-carboxymethyl chitosan nanodroplets were synthesized and functionally tested as drug delivery system in vitro. Materials & methods: The characteristics, charge conversion, stability, cytotoxicity, ultrasound imaging ability, interaction with tumor cells of the nanodroplets and eradication on tumor cells of the doxorubicin-loaded nanodroplets were investigated. Results: O-CS NDs (below 200 nm) achieved higher tumor cellular associations at acidic pH, with great serum stability, pH-dependent charge conversion and good ultrasound imaging ability. Doxorubicin-loading O-carboxymethyl chitosan nanodroplets exhibited strong cytotoxicity on PC-3 cells with ultrasound exposure. Conclusion: These stable, safe and smart O-CS NDs may be a promising approach to improve cell interaction efficiency as an ultrasound imaging and cancer-targeting drug delivery system.

Polymeric nanodroplets: an emerging trend in gaseous delivery system

Currently, nanotechnology-based products are gaining tremendous interest in the development of nanocarriers for drug delivery and nano-diagnostic devices. Nanodroplets (NDs) emerge as novel carriers for delivery of gases and actives with a wide range of applications in fields of theranostics, drug delivery and diagnostic devices. NDs are multifunctional carriers composed of an outer shell of drug and polymer that encapsulates the inner core of gases and liquid molecules. This review focuses on properties of NDs, mathematical theories, different polymers used in the preparation of NDs, characterisation, animal models, toxicity and applications of NDs. These nanocarriers are advantageous due to their cost-effectiveness and compatibility with both gaseous and liquid core molecules. NDs are increasingly utilised in the field of healthcare due to their properties like large effective surface area for drug loading and target specificity. These nanocarriers are also employed in the treatment of hypoxia, multiple sclerosis and cancer. In the near future, NDs will advance in fields of personalised medicine and precise theranostics.

Doxorubicin release by magnetic inductive heating and in vivo hyperthermia-chemotherapy combined cancer treatment of multifunctional magnetic nanoparticles

Multifunctional nanosystems help to control drug release and highly improve the cancer treatment efficacy in in vivo models.