Exploring the Applicability of Nano-Poration for Remote Control in Smart Drug Delivery Systems

Stimuli-responsive biomaterials: smart avenue toward 4D bioprinting

3D bioprinting is an advanced technology combining cells and bioactive molecules within a single bioscaffold; however, this scaffold cannot change, modify or grow in response to a dynamic implemented environment. Lately, a new era of smart polymers and hydrogels has emerged, which can add another dimension, e.g., time to 3D bioprinting, to address some of the current approaches' limitations. This concept is indicated as 4D bioprinting. This approach may assist in fabricating tissue-like structures with a configuration and function that mimic the natural tissue. These scaffolds can change and reform as the tissue are transformed with the potential of specific drug or biomolecules released for various biomedical applications, such as biosensing, wound healing, soft robotics, drug delivery, and tissue engineering, though 4D bioprinting is still in its early stages and more works are required to advance it. In this review article, the critical challenge in the field of 4D bioprinting and transformations from 3D bioprinting to 4D phases is reviewed. Also, the mechanistic aspects from the chemistry and material science point of view are discussed too.

Enhancing electroporation-induced liposomal drug release in suspension and solid phases

When exposed to an external electric field, lipid bilayer membranes are subject to increased permeability through the generation of pores. Combining this phenomenon, known as electroporation, with liposomal drug delivery offers the added benefit of on-demand release of the liposomal cargo. In previous studies, the maximum percent drug release when exposing liposomes to a pulsed electric field has not surpassed 30%, indicating most of the drug is still retained in the liposomes. Here we showed that by modulating the fluidity of the liposome membrane through appropriate selection of the primary lipid, as well as the addition of other fluidity modulating components such as cholesterol and biotinylated lipid, the electroporation-induced percent release could be increased to over 50%. In addition to improved induced release from liposomes in suspension, biomaterial scaffold-bound liposomes were developed. Electroporation-induced protein release from this solid phase was verified after performing further optimization of the liposome formulation to achieve increased stability at physiological temperatures. Collectively, this work advances the ability to achieve efficient electroporation-induced liposomal drug delivery, which has the potential to be used in concert with other clinical applications of electroporation, such as gene electrotransfer and irreversible electroporation (IRE), in order to synergistically increase treatment efficacy.

Electroporation in Head-and-Neck Cancer: An Innovative Approach with Immunotherapy and Nanotechnology Combination

Squamous cell carcinoma is the most common malignancy that arises in the head-and-neck district. Traditional treatment could be insufficient in case of recurrent and/or metastatic cancers; for this reason, more selective and enhanced treatments are in evaluation in preclinical and clinical trials to increase in situ concentration of chemotherapy drugs promoting a selectively antineoplastic activity. Among all cancer treatment types (i.e., surgery, chemotherapy, radiotherapy), electroporation (EP) has emerged as a safe, less invasive, and effective approach for cancer treatment. Reversible EP, using an intensive electric stimulus (i.e., 1000 V/cm) applied for a short time (i.e., 100 μs), determines a localized electric field that temporarily permealizes the tumor cell membranes while maintaining high cell viability, promoting cytoplasm cell uptake of antineoplastic agents such as bleomycin and cisplatin (electrochemotherapy), calcium (Ca²⁺ electroporation), siRNA and plasmid DNA (gene electroporation). The higher intracellular concentration of antineoplastic agents enhances the antineoplastic activity and promotes controlled tumor cell death (apoptosis). As secondary effects, localized EP (i) reduces the capillary blood flow in tumor tissue ("vascular lock"), lowering drug washout, and (ii) stimulates the immune system acting against cancer cells. After years of preclinical development, electrochemotherapy (ECT), in combination with bleomycin or cisplatin, is currently one of the most effective treatments used for cutaneous metastases and primary skin and mucosal cancers that are not amenable to surgery. To reach this clinical evidence, in vitro and in vivo models were preclinically developed for evaluating the efficacy and safety of ECT on different tumor cell lines and animal models to optimize dose and administration routes of drugs, duration, and intensity of the electric field. Improvements in reversible EP efficacy are under evaluation for HNSCC treatment, where the focus is on the development of a combination treatment between EP-enhanced nanotechnology and immunotherapy strategies.

SN38-based albumin-binding prodrug for efficient targeted cancer chemotherapy

Developing new therapeutic strategies that damage tumour cells without harming normal tissues is among the primary obstacles in chemotherapy. In this study, a novel β-glucuronidase-sensitive albumin-binding prodrug was designed and synthesized to selectively deliver the drug SN38 to tumour sites and maximize its efficacy. After intravenous administration, the prodrug Mal-glu-SN38 covalently bound to plasma albumin through the Michael addition, enabling it to accumulate in the tumour and release SN38 when triggered by extracellular β-glucuronidase. Compared to irinotecan, Mal-glu-SN38 displayed a slower plasma clearance and increased drug exposure over time. Moreover, Mal-glu-SN38 caused an increase in tumour-site accumulation of both the albumin-prodrug conjugate and free SN38 released from albumin conjugate when compared with irinotecan. After administration of multiple doses, Mal-glu-SN38 also significantly delayed the tumour growth, resulting in an impressive reduction or even disappearance of tumours (67% of mice cured) without causing any observable side effects.

Proof-of-Concept of Electrical Activation of Liposome Nanocarriers: From Dry to Wet Experiments

The increasing interest toward biocompatible nanotechnologies in medicine, combined with electric fields stimulation, is leading to the development of electro-sensitive smart systems for drug delivery applications. To this regard, recently the use of pulsed electric fields to trigger release across phospholipid membranes of liposomes has been numerically studied, for a deeper understanding of the phenomena at the molecular scale. Aim of this work is to give an experimental validation of the feasibility to control the release from liposome vesicles, using nanosecond pulsed electric fields characterized by a 10 ns duration and intensity in the order of MV/m. The results are supported by multiphysics simulations which consider the coupling of three physics (electromagnetics, thermal and pore kinetics) in order to explain the occurring physical interactions at the microscopic level and provide useful information on the characteristics of the train of pulses needed to obtain quantitative results in terms of liposome electropermeabilization. Finally, a complete characterization of the exposure system is also provided to support the reliability and validity of the study.

Feasibility of Drug Delivery Mediated by Ultra-Short and Intense Pulsed Electric Fields

The increasing interest towards biocompatible nanotechnologies in medicine, combined with electric fields stimulation, is leading to the development of electro-sensitive smart systems for drug delivery applications. Common examples of electro-sensitive materials include phospholipids that can be used to design nano-sized vesicles suitable for external electric actuation. To this regard, recently the use of pulsed electric fields to trigger release across phospholipid membranes has been numerically studied, for a deeper understanding of the phenomena at the molecular scale. Aim of this work is to give an experimental validation of the feasibility of controlling drug release from liposomes mediated by nanosecond pulsed electric fields.

Stimuli-Responsive Drug Release from Smart Polymers

Over the past 10 years, stimuli-responsive polymeric biomaterials have emerged as effective systems for the delivery of therapeutics. Persistent with ongoing efforts to minimize adverse effects, stimuli-responsive biomaterials are designed to release in response to either chemical, physical, or biological triggers. The stimuli-responsiveness of smart biomaterials may improve spatiotemporal specificity of release. The material design may be used to tailor smart polymers to release a drug when particular stimuli are present. Smart biomaterials may use internal or external stimuli as triggering mechanisms. Internal stimuli-responsive smart biomaterials include those that respond to specific enzymes or changes in microenvironment pH; external stimuli can consist of electromagnetic, light, or acoustic energy; with some smart biomaterials responding to multiple stimuli. This review looks at current and evolving stimuli-responsive polymeric biomaterials in their proposed applications.

Redox-Responsive Dual Chemophotothermal Therapeutic Nanomedicine for Imaging-Guided Combinational Therapy

Chemotherapy is currently the major therapeutic method against cancer. However, chemo drugs are usually lacking in the specificity towards cancer cells over normal cells. In this study, we prepared a novel multifunctional trimeric prodrug by linking the chemo drug camptothecin (CPT) and the exceptional photostable near infrared (NIR) croconaine dye (CR) via a glutathione (GSH)-sensitive disulfide linker. Compared with CPT, our novel trimeric CR-(SS-CPT)2 is more hydrophobic and bulky, making it highly effcient to be encapsulated into biocompatible polymeric nanocarrier. The prodrug underwent rapid drug release specifically in cancer cells with high GSH concentration. The hyperthermia produced by CR upon laser irradiation could further accelerate the break of disulfide bond, which makes the release of CPT even more controllable. We further loaded the CR-(SS-CPT)2 into folate modified lipid-polymer nanoparticles, which demonstrated high in vivo tumor accumulation and retention. The biodistribution of these nanoparticles can be directly monitored in real time via NIR fluorescence and photoacoustic imaging. Under the imaging guided chemo- and photothermal- synergistic therapy, the tumors were completely ablated with no recurrence. The design not only highly enhanced the therapeutic specificity and effeciency of CPT, but also provide a "all in one" nanomedicine for imaging-guided dual modality therapy.

A wide-band bio-chip for real-time optical detection of bioelectromagnetic interactions with cells

The analytical and numerical design, implementation, and experimental validation of a new grounded closed coplanar waveguide for wide-band electromagnetic exposures of cells and their optical detection in real-time is reported. The realized device fulfills high-quality requirements for novel bioelectromagnetic experiments, involving elevated temporal and spatial resolutions. Excellent performances in terms of matching bandwidth (less than -10 dB up to at least 3 GHz), emission (below 1 × 10^-6 W/m²) and efficiency (around 1) have been obtained as revealed by both numerical simulations and experimental measurements. A low spatial electric field inhomogeneity (coefficient of variation of around 10 %) has been achieved within the cell solutions filling the polydimethylsiloxane reservoir of the conceived device. This original bio-chip based on the grounded closed coplanar waveguide concept opens new possibilities for the development of controlled experiments combining electromagnetic exposures and sophisticated imaging using optical spectroscopic techniques.

Technological and Theoretical Aspects for Testing Electroporation on Liposomes

Recently, the use of nanometer liposomes as nanocarriers in drug delivery systems mediated by nanoelectroporation has been proposed. This technique takes advantage of the possibility of simultaneously electroporating liposomes and cell membrane with 10-nanosecond pulsed electric fields (nsPEF) facilitating the release of the drug from the liposomes and at the same time its uptake by the cells. In this paper the design and characterization of a 10 nsPEF exposure system is presented, for liposomes electroporation purposes. The design and the characterization of the applicator have been carried out choosing an electroporation cuvette with 1 mm gap between the electrodes. The structure efficiency has been evaluated at different experimental conditions by changing the solution conductivity from 0.25 to 1.6 S/m. With the aim to analyze the influence of device performances on the liposomes electroporation, microdosimetric simulations have been performed considering liposomes of 200 and 400 nm of dimension with different inner and outer conductivity (from 0.05 to 1.6 S/m) in order to identify the voltage needed for their poration.