Cancer Therapy Based on Smart Drug Delivery with Advanced Nanoparticles

Preparation, characterization, and in-vitro cytotoxicity of nanoliposomes loaded with anti-tubercular drugs and TGF-β1 siRNA for improving spinal tuberculosis therapy

Background

Tuberculosis (TB) represents a bacterial infection affecting many individuals each year and potentially leading to death. Overexpression of transforming growth factor (TGF)-β1 has a primary immunomodulatory function in human tuberculosis. This work aimed to develop nanoliposomes to facilitate the delivery of anti-tubercular products to THP-1-derived human macrophages as Mycobacterium host cells and to evaluate drug efficiencies as well as the effects of a TGF-β1-specific short interfering RNA (siRNA) delivery system employing nanoliposomes.

Methods

In the current study, siTGF-β1 nanoliposomes loaded with the anti-TB drugs HRZ (isoniazid, rifampicin, and pyrazinamide) were prepared and characterized in vitro, determining the size, zeta potential, morphology, drug encapsulation efficiency (EE), cytotoxicity, and gene silencing efficiency of TGF-β1 siRNA.

Results

HRZ/siTGF-β1 nanoliposomes appeared as smooth spheres showing the size and positive zeta potential of 168.135 ± 0.5444 nm and + 4.03 ± 1.32 mV, respectively. Drug EEs were 90%, 88%, and 37% for INH, RIF, and PZA, respectively. Meanwhile, the nanoliposomes were weakly cytotoxic towards human macrophages as assessed by the MTT assay. Nanoliposomal siTGF-β1 could significantly downregulate TGF-β1 in THP-1-derived human macrophages in vitro.

Conclusion

These findings suggested that HRZ-loaded nanoliposomes with siTGF-β1 have the potential for improving spinal tuberculosis chemotherapy via nano-encapsulation of anti-TB drugs.

Cellulose nanofibers as Scaffold-forming materials for thin film drug delivery systems

We explored the potential of cellulose nanofiber (CNF) for designing prolonged-release, thin-film drug delivery systems (TF-DDS). These delivery systems can be used as locally deployable drug-releasing scaffolds for achieving spatial and temporal control over therapeutic concentration in target tissues. Using doxorubicin (DOX) as a model anticancer drug, CNF-based TF-DDS were prepared using different film-formation processes, such as solvent casting and lyophilization. Formulations were prepared with or without the incorporation of additional macromolecular additives, such as gelatin, to include further biomechanical functionality. We studied the films for their mechanical properties, thermal stability, wettability, porosity and in vitro drug release properties. Our experimental results showed that CNF-based films, when prepared via solvent casting method, showed optimized performance in terms of DOX loading, and prolonged-release than those prepared via lyophilization-based fabrication processes. Scanning electron microscopy (SEM) analysis of the CNF-based films showed uniform distribution of fiber entanglement, which provided the scaffolds with sufficient porosity and tortuosity contributing to the sustained release of the drug from the delivery system. We also observed that surface layering of gelatin on CNF films via dip-coating significantly increased the mechanical strength and reduced the wettability of the films, and as such, affected drug release kinetics. The performance of the TF-DDS was evaluated in-vitro against two pancreatic cancer cell lines, i.e. MIA PaCa-2 and PANC-1. We observed that, along with the enhancement of mean dissolution time (MDT) of DOX, CNF-based TF-DDS were able to suppress the proliferation of pancreatic cancer cells in a time-dependent fashion, indicating that the drug liberated from the films were therapeutically active against cancer cells. Additionally, TF-DDS were also tested ex-vivo on patient-derived xenograft (PDX) model of pancreatic ductal adenocarcinoma (PDAC). We observed that DOX released from the TF-DDS was able to reduce Ki-67 positive, pancreatic cancer cells in these models.

Liposome as a delivery system for the treatment of biofilm-mediated infections

Biofilm formation by pathogenic microorganisms has been a tremendous challenge for antimicrobial therapies due to various factors. The biofilm matrix sequesters bacterial cells from the exterior environment and therefore prevents antimicrobial agents from reaching the interior. In addition, biofilm surface extracellular polymeric substances can absorb antimicrobial agents and thus reduce their bioavailability. To conquer these protection mechanisms, liposomes have been developed into a drug delivery system for antimicrobial agents against biofilm-mediated infections. The unique characteristics of liposomes, including versatility for cargoes, target-specificity, nonimmunogenicity, low toxicity, and biofilm matrix-/cell membrane-fusogenicity, remarkably improve the effectiveness of antimicrobial agents and minimize recurrence of infections. This review summarizes current development of liposomal carriers for biofilm therapeutics, presents evidence in their practical applications and discusses their potential limitations.

Recent advances of two-dimensional materials in smart drug delivery nano-systems

Smart drug delivery nano-systems show significant changes in their physical or chemical properties in response to slight change in environmental physical and/or chemical signals, and further releasing drugs adjusted to the progression of the disease at the right target and rate intelligently. Two-dimensional materials possess dramatic status extend all over various scientific and technological disciplines by reason of their exceptional unique properties in application of smart drug delivery nano-systems. In this review, we summarized current progress to highlight various kinds of two-dimensional materials drug carriers which are widely explored in smart drug delivery systems as well as classification of stimuli responsive two-dimensional materials and the advantages and disadvantages of their applications. Consequently, we anticipate that this review might inspire the development of new two-dimensional materials with smart drug delivery systems, and deepen researchers' understanding of smart nano-carries based on two-dimensional materials.

Lipid-Based Antimicrobial Delivery-Systems for the Treatment of Bacterial Infections

Many nanotechnology-based antimicrobials and antimicrobial-delivery-systems have been developed over the past decades with the aim to provide alternatives to antibiotic treatment of infectious-biofilms across the human body. Antimicrobials can be loaded into nanocarriers to protect them against de-activation, and to reduce their toxicity and potential, harmful side-effects. Moreover, antimicrobial nanocarriers such as micelles, can be equipped with stealth and pH-responsive features that allow self-targeting and accumulation in infectious-biofilms at high concentrations. Micellar and liposomal nanocarriers differ in hydrophilicity of their outer-surface and inner-core. Micelles are self-assembled, spherical core-shell structures composed of single layers of surfactants, with hydrophilic head-groups and hydrophobic tail-groups pointing to the micellar core. Liposomes are composed of lipids, self-assembled into bilayers. The hydrophilic head of the lipids determines the surface properties of liposomes, while the hydrophobic tail, internal to the bilayer, determines the fluidity of liposomal-membranes. Therefore, whereas micelles can only be loaded with hydrophobic antimicrobials, hydrophilic antimicrobials can be encapsulated in the hydrophilic, aqueous core of liposomes and hydrophobic or amphiphilic antimicrobials can be inserted in the phospholipid bilayer. Nanotechnology-derived liposomes can be prepared with diameters <100-200 nm, required to prevent reticulo-endothelial rejection and allow penetration into infectious-biofilms. However, surface-functionalization of liposomes is considerably more difficult than of micelles, which explains while self-targeting, pH-responsive liposomes that find their way through the blood circulation toward infectious-biofilms are still challenging to prepare. Equally, development of liposomes that penetrate over the entire thickness of biofilms to provide deep killing of biofilm inhabitants still provides a challenge. The liposomal phospholipid bilayer easily fuses with bacterial cell membranes to release high antimicrobial-doses directly inside bacteria. Arguably, protection against de-activation of antibiotics in liposomal nanocarriers and their fusogenicity constitute the biggest advantage of liposomal antimicrobial carriers over antimicrobials free in solution. Many Gram-negative and Gram-positive bacterial strains, resistant to specific antibiotics, have been demonstrated to be susceptible to these antibiotics when encapsulated in liposomal nanocarriers. Recently, also progress has been made concerning large-scale production and long-term storage of liposomes. Therewith, the remaining challenges to develop self-targeting liposomes that penetrate, accumulate and kill deeply in infectious-biofilms remain worthwhile to pursue.

Lipid-Based Antimicrobial Delivery-Systems for the Treatment of Bacterial Infections

Many nanotechnology-based antimicrobials and antimicrobial-delivery-systems have been developed over the past decades with the aim to provide alternatives to antibiotic treatment of infectious-biofilms across the human body. Antimicrobials can be loaded into nanocarriers to protect them against de-activation, and to reduce their toxicity and potential, harmful side-effects. Moreover, antimicrobial nanocarriers such as micelles, can be equipped with stealth and pH-responsive features that allow self-targeting and accumulation in infectious-biofilms at high concentrations. Micellar and liposomal nanocarriers differ in hydrophilicity of their outer-surface and inner-core. Micelles are self-assembled, spherical core-shell structures composed of single layers of surfactants, with hydrophilic head-groups and hydrophobic tail-groups pointing to the micellar core. Liposomes are composed of lipids, self-assembled into bilayers. The hydrophilic head of the lipids determines the surface properties of liposomes, while the hydrophobic tail, internal to the bilayer, determines the fluidity of liposomal-membranes. Therefore, whereas micelles can only be loaded with hydrophobic antimicrobials, hydrophilic antimicrobials can be encapsulated in the hydrophilic, aqueous core of liposomes and hydrophobic or amphiphilic antimicrobials can be inserted in the phospholipid bilayer. Nanotechnology-derived liposomes can be prepared with diameters <100-200 nm, required to prevent reticulo-endothelial rejection and allow penetration into infectious-biofilms. However, surface-functionalization of liposomes is considerably more difficult than of micelles, which explains while self-targeting, pH-responsive liposomes that find their way through the blood circulation toward infectious-biofilms are still challenging to prepare. Equally, development of liposomes that penetrate over the entire thickness of biofilms to provide deep killing of biofilm inhabitants still provides a challenge. The liposomal phospholipid bilayer easily fuses with bacterial cell membranes to release high antimicrobial-doses directly inside bacteria. Arguably, protection against de-activation of antibiotics in liposomal nanocarriers and their fusogenicity constitute the biggest advantage of liposomal antimicrobial carriers over antimicrobials free in solution. Many Gram-negative and Gram-positive bacterial strains, resistant to specific antibiotics, have been demonstrated to be susceptible to these antibiotics when encapsulated in liposomal nanocarriers. Recently, also progress has been made concerning large-scale production and long-term storage of liposomes. Therewith, the remaining challenges to develop self-targeting liposomes that penetrate, accumulate and kill deeply in infectious-biofilms remain worthwhile to pursue.