Polymeric Nanoparticles Amenable to Simultaneous Installation of Exterior Targeting and Interior Therapeutic Proteins

Factors Influencing the Delivery Efficiency of Cancer Nanomedicines

The superiority of nanomedicine over conventional medicines in the treatment of cancer has gained immediate recognition worldwide. As traditional cancer therapies are nonspecific and detrimental to healthy cells, the ability of nanomedicine to release drugs to target tumor cells specifically instead of healthy cells has brought new hope to cancer patients. This review focuses on the effects of various factors of nanoparticles such as transport, concentration in cells, tumor microenvironment, interaction with protein, penetration, uptake by tumor cells, cancer cell mutations, and intracellular trafficking of the nanoparticle. Besides the history of nanomedicine, future perspectives of nanomedicines are also explored in this text.

Oral Delivery of Biologics for Precision Medicine

The emerging field of precision medicine is rapidly growing, fostered by the advances in genome mapping and molecular diagnosis. In general, the translation of these advances into precision treatments relies on the use of biological macromolecules, whose structure offers a high specificity and potency. Unfortunately, due to their complex structure and limited ability to overcome biological barriers, these macromolecules need to be administered via injection. The scientific community has devoted significant effort to making the oral administration of macromolecules plausible thanks to the implementation of drug delivery technologies. Here, an overview of the current situation and future prospects in the field of oral delivery of biologics is provided. Technologies in clinical trials, as well as recent and disruptive delivery systems proposed in the literature for local and systemic delivery of biologics including peptides, antibodies, and nucleic acids, are described. Strategies for the specific targeting of gastrointestinal regions-stomach, small bowel, and colon-cell populations, and internalization pathways, are analyzed. Finally, challenges associated with the clinical translation, future prospects, and identified opportunities for advancement in this field are also discussed.

Nanoparticle Delivery Systems in the Treatment of Diabetes Complications

Diabetes mellitus, an incurable metabolic disease, is characterized by changes in the homeostasis of blood sugar levels, being the subcutaneous injection of insulin the first line treatment. This administration route is however associated with limited patient's compliance, due to the risk of pain, discomfort and local infection. Nanoparticles have been proposed as insulin carriers to make possible the administration of the peptide via friendlier pathways without the need of injection, i.e., via oral or nasal routes. Nanoparticles stand for particles in the nanometer range that can be obtained from different materials (e.g., polysaccharides, synthetic polymers, lipid) and are commonly used with the aim to improve the physicochemical stability of the loaded drug and thereby its bioavailability. This review discusses the use of different types of nanoparticles (e.g., polymeric and lipid nanoparticles, liposomes, dendrimers, niosomes, micelles, nanoemulsions and also drug nanosuspensions) for improved delivery of different oral hypoglycemic agents in comparison to conventional therapies.

Rational Design of Nanocarriers for Intracellular Protein Delivery

Protein/antibody therapeutics have exhibited the advantages of high specificity and activity even at an extremely low concentration compared to small molecule drugs. However, they are accompanied by unfavorable physicochemical properties such as fragile tertiary structure, large molecular size, and poor penetration of the membrane, and thus the clinical use of protein drugs is hindered by inefficient delivery of proteins into the host cells. To overcome the challenges associated with protein therapeutics and enhance their biopharmaceutical applications, various protein-loaded nanocarriers with desired functions, such as lipid nanocapsules, polymeric nanoparticles, inorganic nanoparticles, and peptides, are developed. In this review, the different strategies for intracellular delivery of proteins are comprehensively summarized. Their designed routes, mechanisms of action, and potential therapeutics in live cells or in vivo are discussed in detail. Furthermore, the perspective on the new generation of delivery systems toward the emerging area of protein-based therapeutics is presented as well.

Orally Administrable Therapeutic Synthetic Nanoparticle for Zika Virus

The spread of Zika virus (ZIKV) infection across the USA and various countries in the last three years will not only have a direct impact on the U.S. health care system but has caused international concerns as well. The ultimate impact of ZIKV infection remains to be understood. Currently, there are no therapeutic or vaccine options available to protect those infected by ZIKV. The drug ivermectin (IVM) was found to be a viable agent for the prevention of transmission of ZIKV. Ivermectin is unstable in the presence of water and does not remain in adequate concentration in the human bloodstream to be effective in treatment for ZIKV. Biodegradable nanoparticles would aid in the delivery of ivermectin by providing a high enough concentration of drug and ensuring the drug is gradually released to maintain an appropriate level in the body. The overall goal of this study was to develop and optimize an orally administrable nanoformulation of IVM which can circulate in the blood for a long period for efficient delivery. To achieve the goal, we synthesized and optimized a synthetic nanoformulation of IVM for oral use which can cross the intestinal epithelial barrier to enter the bloodstream. Our studies documented that when delivered with the synthetic nanoparticle (NP), IVM can be accumulated in the blood at a higher concentration and preliminary studies highlighted that NP delivered IVM has the ability to target nonstructural 1 protein of ZIKV. For potential clinical relevance, long-term storable formulation of IVM-nanoparticle in dry powder state for inclusion in a capsule form and cryoprotectant containing frozen forms revealed promising findings. Further, our preliminary in vitro studies documented that ivermectin crosses the placental barrier, thus making it unsafe for the pregnant ZIKV population, whereas the ivermectin-loaded nanoparticle did not show any significant placental barrier crossing, thus indicating its potential suitability for such population. We envision that this work will fill a great unmet need by developing safer and more effective therapies for the treatment of viral infections, including ZIKV.

Orally Administrable Therapeutic Synthetic Nanoparticle for Zika Virus

The spread of Zika virus (ZIKV) infection across the USA and various countries in the last three years will not only have a direct impact on the U.S. health care system but has caused international concerns as well. The ultimate impact of ZIKV infection remains to be understood. Currently, there are no therapeutic or vaccine options available to protect those infected by ZIKV. The drug ivermectin (IVM) was found to be a viable agent for the prevention of transmission of ZIKV. Ivermectin is unstable in the presence of water and does not remain in adequate concentration in the human bloodstream to be effective in treatment for ZIKV. Biodegradable nanoparticles would aid in the delivery of ivermectin by providing a high enough concentration of drug and ensuring the drug is gradually released to maintain an appropriate level in the body. The overall goal of this study was to develop and optimize an orally administrable nanoformulation of IVM which can circulate in the blood for a long period for efficient delivery. To achieve the goal, we synthesized and optimized a synthetic nanoformulation of IVM for oral use which can cross the intestinal epithelial barrier to enter the bloodstream. Our studies documented that when delivered with the synthetic nanoparticle (NP), IVM can be accumulated in the blood at a higher concentration and preliminary studies highlighted that NP delivered IVM has the ability to target nonstructural 1 protein of ZIKV. For potential clinical relevance, long-term storable formulation of IVM-nanoparticle in dry powder state for inclusion in a capsule form and cryoprotectant containing frozen forms revealed promising findings. Further, our preliminary in vitro studies documented that ivermectin crosses the placental barrier, thus making it unsafe for the pregnant ZIKV population, whereas the ivermectin-loaded nanoparticle did not show any significant placental barrier crossing, thus indicating its potential suitability for such population. We envision that this work will fill a great unmet need by developing safer and more effective therapies for the treatment of viral infections, including ZIKV.

Cysteine-based redox-responsive nanoparticles for small-molecule agent delivery

As a significant part of molecular-targeted therapies, small-molecule agents (SMAs) have been increasingly used for cancer treatment. Nevertheless, most SMAs are currently administered orally due to their poor solubility, resulting in a low bioavailability and unavoidable side effects. Herein, we proposed a promising SMA delivery strategy using a biocompatible and redox-responsive nanoparticle (NP) delivery system to improve their bioavailability, alleviate side effects and enhance therapeutic performance. To demonstrate the feasibility of this strategy, a type of cysteine-based hydrophobic polymer was employed to construct a redox-sensitive nanoplatform for the delivery of various hydrophobic oral SMAs. These SMA-loaded nanoparticles (SMA-NPs) all have a small particle size and good drug-loading capacity. Particularly, lapatinib-loaded nanoparticles (LAP-NPs) with a minimal particle size (79.71 nm) and an optimal drug-loading capacity (12.5%) were utilized as a model to systemically explore the in vitro and in vivo anticancer potential of SMA-NPs. As expected, the LAP-NPs exhibited rapid redox-responsive drug release, enhanced in vitro cytotoxicity and cell apoptosis, and demonstrated notable anti-metastasis ability and desirable intracellular localization. Additionally, the in vivo results demonstrated the preferential accumulation of LAP-NPs in tumor tissues and the significant suppression of tumor growth. Therefore, the generated SMA-NP delivery system shows great SMA delivery potential for advanced molecular-targeted therapies.

Drug Delivery Strategies for the Treatment of Metabolic Diseases

Metabolic diseases occur when normal metabolic processes are disrupted in the human body, which can be congenital or acquired. The incidence of metabolic diseases worldwide has reached epidemic proportions. So far, various methods including systemic drug therapy and surgery are exploited to prevent and treat metabolic diseases. However, current pharmacotherapeutic options for treatment of these metabolic disorders remain limited and ineffective, especially reducing patient compliance to treatment. Therefore, it is desirable to exploit effective drug delivery approaches to effectively treat metabolic diseases and reduce side effects. This brief review summarizes novel delivery strategies including local, targeted, and oral drug delivery strategies, as well as intelligent stimulus-responsive drug delivery strategy, for the treatment of metabolic disorders including diabetes, obesity, and atherosclerosis.

Nanoparticle Therapy for Prostate Cancer: Overview and Perspectives

Traditional prostate cancer therapy and especially chemotherapy has faced many challenges. Low accumulation levels, rapid clearance or drug resistance at the tumor site have been central to why the effect of chemotherapy drugs has declined. Applications of nanotechnology to biomedicine have enabled the development of nanoparticle therapeutic carriers suited for the delivery of chemotherapeutics in cancer therapy. This review describes the current nature of nanoparticle therapeutic carriers for prostate cancer. It describes typical nanocarriers commonly used for the delivery of chemotherapy or for imaging examination. Targeting strategies and related influencing factors are investigated to find ways of enhancing treatment effects of nanoparticles. The overall purpose of this review is to further understanding and to offer recommendations on the design and development of therapeutic nanoparticles for prostate cancer.

Synthesis of CSK-DEX-PLGA Nanoparticles for the Oral Delivery of Exenatide to Improve Its Mucus Penetration and Intestinal Absorption

The oral absorption of exenatide, a drug for type 2 diabetes treatment, can be improved by using nanoparticles (NPs) for its delivery. To improve the mucus penetration and intestinal absorption of exenatide, we designed a block copolymer, CSKSSDYQC-dextran-poly(lactic-co-glycolic acid) (CSK-DEX-PLGA), and used it for the preparation of exenatide-loaded NPs. The functionalized exenatide-loaded NPs composed of CSK-DEX-PLGA were able to target intestinal epithelial cells and reduce the mucus-blocking effect of the intestine. Moreover, the CSK modification of DEX-PLGA was found to significantly promote the absorption efficiency of NPs in the small intestine based on in vitro ligation of the intestinal rings and an examination of different intestinal absorption sites. Compared to DEX-PLGA-NPs (DPs), the absorption of CSK-DEX-PLGA-NPs (CDPs) was increased in the villi, allowing the drug to act on gobletlike Caco-2 cells through clathrin-, caveolin-, and gap-mediated endocytosis. Furthermore, the enhanced transport ability of CDPs was observed in a study on Caco-2/HT-29-MTX cocultured cells. CDPs exhibited a prolonged hypoglycemic response with a relative bioavailability of 9.2% in diabetic rats after oral administration. In conclusion, CDPs can target small intestinal goblet cells and have a beneficial effect on the oral administration of macromolecular peptides as a nanometer-sized carrier.

Screening of pH-responsive long-circulating polysaccharide–drug conjugate nanocarriers for antitumor applications

Schematic illustration of the development of long-circulating pH-responsive polysaccharide–DOX prodrug nanoparticles for antitumor applications.

Cancer nanomedicine: focus on recent developments and self-assembled peptide nanocarriers

The applications of nanoparticulate drug delivery have received abundant interest in the field of cancer diagnosis and treatment.

Delivery of tacrolimus with cationic lipid-assisted nanoparticles for ulcerative colitis therapy

Oral drug delivery with nanoparticles has demonstrated great potential for drugs with poor bioavailability. Efficient delivery is possible by overcoming both the mucus and epithelial barrier of the gastrointestinal tract (GIT). Cationic lipid-assisted nanoparticles (CLANs), which are composed of amphiphilic block copolymers and cationic lipids, have been well studied and have been proved beneficial for drug delivery. In this study, CLANs prepared by poly(ethylene glycol)-block-poly(lactic acid) (PEG-b-PLA) and 1,2-dioleoyl-3-trimethylammonium-propanechloride (DOTAP) or N,N-bis(2-hydroxyethyl)-N-methyl-N-(2-cholesteryloxycarbonyl aminoethyl)ammoniumbromide (BHEM-Chol) were used for oral delivery of tacrolimus (FK506) for ulcerative colitis treatment. The average size of these nanoparticles is around 110 nm and the zeta-potential is 35 mV. These nanoparticles maintained their size in buffer solutions of pH 1.2 and 6.8, and slowly release the encapsulated drug. CLANs can be accumulated in the colon and transported through the epithelium in the colitis model by dextran sulfate sodium salt (DSS), leading to attenuation of DSS-induced colitis.

Dipeptide-modified nanoparticles to facilitate oral docetaxel delivery: new insights into PepT1-mediated targeting strategy

Oligopeptide transporter 1 (PepT1) has been a striking prodrug-designing target. However, the underlying mechanism of PepT1 as a target to facilitate the oral absorption of nanoparticles (NPs) remains unclear. Herein, we modify Poly (lactic-co-glycolic acid) (PLGA) NPs with the conjugates of dipeptides (L-valine-valine, L-valine-phenylalanine) and polyoxyethylene (PEG Mw: 1000, 2000) stearate to facilitate oral delivery of docetaxel (DTX) to investigate the oral absorption mechanism and regulatory effects on PepT1 of the dipeptide-modified NPs. The cellular uptake of the dipeptide-modified NPs is more efficient than that of the unmodified NPs in the stably transfected hPepT1- Hela cells and Caco-2 cells, suggesting the involvement of PepT1 in the endocytosis of NPs. The internalization of the dipeptide-modified NPs is proved to be a proton-dependent process. Moreover, the L-valine-valine modified NPs with shorter PEG chain exhibit distinct advantages in terms of intestinal permeability and oral absorption, resulting in significantly improved oral bioavailability of DTX. In summary, PepT1 could serve as a desirable target for oral nanoparticulate drug delivery and the dipeptide-modified NPs represent a promising nanoplatform to facilitate oral delivery of hydrophobic drugs with low bioavailability.

Multifunctional Nanoparticles Enable Efficient Oral Delivery of Biomacromolecules via Improving Payload Stability and Regulating the Transcytosis Pathway

In oral delivery of biomacromolecules, ligand-modified nanoparticles (NPs) have emerged as a promising tool to improve the epithelial uptake of the loaded protein/peptide. Unfortunately, the stability and the transport mechanisms of the biotherapeutics during the intracellular transportation still remained unclear, leading to the poor transepithelial efficiency. Additionally, developing novel approaches to simultaneously monitor the payload bioactivity during the transport processes is veritably benefit for keeping their bioactivity. In the present study, EGP peptide (KRKKKGKGLGKKRDPCLRKYK), a ligand with high affinity to heparan sulfate proteoglycans (HSPGs), was found remarkably increasing the cellular uptake (4.5-fold) and also surprisingly achieving high transcytosis efficiency (4.2-fold) of poly(lactide- co-glycolide) NPs on Caco-2 cell monolayer. Compared with unmodified NPs (C NPs), EGP modified NPs (EGP NPs) exhibited more desirable colloidal stability within epithelia. In the subsequent study, the bioactivity of encapsulated insulin during the cellular transportation was innovatively monitored by a glucose consumption assay. Inspiringly, EGP NPs could mostly retain the bioactivity of loaded insulin whereas insulin from INS-C NPs was significantly degraded. Then the detailed mechanism study revealed that the binding of EGP to HSPGs played a vital role on NP transportation. Unlike C NPs being delivered in the endo/lysosomal pathway, EGP NPs were involved in caveolae-mediated transport, which contributes to the efficient avoidance of the lysosomal entrapment and sequentially facilitates the direct apical-to-basolateral transcytosis. The enhanced absorption of EGP NPs was confirmed in in situ intestinal loop models. Most importantly, oral administrated INS-EGP NPs generated a strong hypoglycemic response on diabetic rats with 10.2-fold and 2.6-fold increase in bioavailability compared with free insulin and INS-C NPs, respectively. The work provided an innovative strategy to monitor the payload bioactivity during the transport processes and proposed a novel aspect to increase oral bioavailability of biomacromolecules via improving payload stability and regulating the transcytosis pathway of nanocarriers.

Biomimetic Shells Endow Sub-50 nm Nanoparticles with Ultrahigh Paclitaxel Payloads for Specific and Robust Chemotherapy

Poor loading capacity and nonspecific tumor accumulation of current drug delivery system remain the critical challenges that prevent nanomedicine from maximizing therapeutic efficacy in cancer treatment. Herein, poly(ester amide) polymers composed of cationic and hydrophobic segments were formulated with a paclitaxel/human serum albumin (PTX/HSA) complex, as well as free PTX, to construct a core-shell nanoparticle (NP) platform with the interior simultaneously reserving PTX and PTX/HSA complex, while the exterior absorbing the PTX/HSA complex. Following systematic screening, the optimized NPs, namely, APP1i@e NPs, exhibited small particle size (43.95 nm), maximal PTX loading (42.23%), excellent dynamic stability (at least 1 week), and acid-triggered release. In vitro results showed that after being trafficked through caveolae-mediated endocytosis, APP1i@e NPs successfully escaped from endo-/lysosomes and then rapidly released cargos in the acidic cytosol, which continued to enhance cytotoxicity by mitochondrial control of apoptosis and suppression of microtubule dynamics. Longer circulation time and superior targeting efficiency post-intravenous injection confirmed that surface PEGylation imparted APP1i@e NPs with the ability to control their pharmacokinetics and biodistribution. The biomimetic shell design with HSA, which enlarged PTX stock and improved biosafety, made APP1i@e NPs more suitable for in vivo applications. Furthermore, in vivo safety and efficacy demonstrated that APP1i@e NPs effectively inhibited the growth of ovarian xenograft tumors, whereas significantly avoiding toxic issues associated with PTX. APP1i@e NPs with surface PEG coating and biomimetic HSA design, therefore, may provide a remarkable improvement in the therapeutic index of taxanes used in the clinic.

Tailoring Platinum(IV) Amphiphiles for Self-Targeting All-in-One Assemblies as Precise Multimodal Theranostic Nanomedicine

Drug, targeting ligand, and imaging agent are the three essential components in a nanoparticle-based drug delivery system. However, tremendous batch-to-batch variation of composition and drug content typically accompany the current approaches of building these components together. Herein, we report the design of photoactivatable platinum(IV) (Pt(IV)) amphiphiles containing one or two hydrophilic lactose targeting ligands per hydrophobic Pt(IV) prodrug for an all-in-one precise nanomedicine. Self-assembly of these Pt(IV) amphiphiles results in either micelle or vesicle formation with a fixed Pt/targeting moiety ratio and a constantly high content of Pt. The micelles and vesicles are capable of hepatoma cell-targeting, fluorescence/Pt-based CT imaging and have shown effective anticancer efficacy under laser irradiation in vitro and in vivo. This photoactivatable, active self-targeting, and multimodal theranostic amphiphile strategy shows great potential in constructing precise nanomedicine.

Dynamic and programmable morphology and size evolution via a living hierarchical self-assembly strategy

Recent advances in the preparation of shape-shifting and size-growing nanostructures are hot topics in development of nanoscience, because many intelligent functions are always relied on their shape and dimension. Here we report a tunable manipulation of sequential self-assembled transformation in situ via a hierarchical assembly strategy based on a living thiol-disulfide exchange reaction. By tailoring the external stimuli, the reactive points can be generated at the ends of initially unimolecular micelles, which subsequently drive the pre-assemblies to periodically proceed into the hierarchically micellar connection, axial growth, bending, and cyclization processes from nanoscopic assemblies to macroscopic particles. Of particular interest would be systems that acquired the shape control and size adjustment of self-assemblies after termination or reactivation of disulfide reshuffling reaction by regulating external stimuli whenever needed. Such a hierarchical strategy for self-assembled evolution is universally applicable not only for other disulfide-linked dendritic polymers but also for exploitation of biological applications.

Advance in oral delivery systems for therapeutic protein

Oral delivery is the most common method of drug administration with high safety and good compliance for patients. However, delivering therapeutic proteins to the target site via oral route involves tremendous challenge due to unfavourable conditions like biochemical barrier, mucus barrier and epithelial barriers. According to the functional differences of various protein drug delivery systems, the recent advances in pH responsive polymer-based drug delivery system, mucoadhesive polymer-based drug delivery system, absorption enhancers-based drug delivery system and composite polymer-based delivery system all were briefly summarised in this review, which not only clarified the clinic potential of these novel drug delivery systems, but also described the way for increasing oral bioavailability of therapeutic protein.

Self-assembly of peptide amphiphiles for drug delivery: the role of peptide primary and secondary structures

Peptide amphiphiles (PAs), functionalized with alkyl chains, are capable of self-assembling into various nanostructures. Recently, PAs have been considered as ideal drug carriers due to their good biocompatibility, specific biological functions, and hypotoxicity to normal cells and tissues. Meanwhile, the nanocarriers formed by PAs are able to achieve controlled drug release and enhanced cell uptake in response to the stimulus of the physiological environment or specific biological factors in the location of the lesion. However, the underlying detailed drug delivery mechanism, especially from the aspect of primary and secondary structures of PAs, has not been systematically summarized or discussed. Focusing on the relationship between the primary and secondary structures of PAs and stimuli-responsive drug delivery applications, this review highlights the recent advances, challenges, and opportunities of PA-based functional drug nanocarriers, and their potential pharmaceutical applications are discussed.

Novel Solid Lipid Nanoparticle with Endosomal Escape Function for Oral Delivery of Insulin

Although nanoparticles (NPs) have been demonstrated as promising tools for improving oral absorption of biotherapeutics, most of them still have very limited oral bioavailability. Lyso-endosomal degradation in epithelial cells is one of the important but often-neglected physiological barriers, limiting the transport of cargoes across the intestinal epithelium. We herein reported a solid lipid nanoparticle (SLN) platform with a unique feature of endosomal escape for oral protein drug delivery. The SLNs consisted of a solid-lipid shell, which contained an endosomal escape agent (GLFEAIEGFIENGWEGMIDGWYG, HA2), and an aqueous core that is loaded with insulin (INS HA2-O-SLNs). SLNs without and with the HA2 peptide in the aqueous core (INS SLNs and INS HA2-W-SLNs, respectively) were used as the control groups. Our study showed that INS HA2-O-SLNs effectively facilitated the escape of the loaded insulin from the acidic endosomes, which preserved the biological activity of insulin to a greater extent during the intracellular transport. The spatial location of the HA2 peptide was demonstrated to determine the endosomal escape efficiency. As demonstrated in the intracellular trafficking of SLNs, INS HA2-O-SLNs displayed much less distribution in late endosomes and lysosomes. Meanwhile, insulin in INS HA2-O-SLNs exhibited the highest transepithelial permeation efficiency, with 2.19 and 1.72 folds higher accumulated amount in the basolateral side as compared to that in INS SLNs and INS HA2-W-SLNs. In addition, insulin from INS HA2-O-SLNs exhibited the highest insulin permeation in various regions of small intestines. INS HA2-O-SLNs generated an excellent hypoglycemic response following oral administration in diabetic rats. Thus, such functional SLNs demonstrated a great potency for oral delivery of peptide/protein drugs.

Polydopamine-Functionalized CA-(PCL-ran-PLA) Nanoparticles for Target Delivery of Docetaxel and Chemo-photothermal Therapy of Breast Cancer

Current limitations of cancer therapy include the lack of effective strategy for target delivery of chemotherapeutic drugs, and the difficulty of achieving significant efficacy by single treatment. Herein, we reported a synergistic chemo-photothermal strategy based on aptamer (Apt)-polydopamine (pD) functionalized CA-(PCL-ran-PLA) nanoparticles (NPs) for effective delivery of docetaxel (DTX) and enhanced therapeutic effect. The developed DTX-loaded Apt-pD-CA-(PCL-ran-PLA) NPs achieved promising advantages, such as (i) improved drug loading content (LC) and encapsulation efficiency (EE) initiated by star-shaped copolymer CA-(PCL-ran-PLA); (ii) effective target delivery of drugs to tumor sites by incorporating AS1411 aptamers; (iii) significant therapeutic efficacy caused by synergistic chemo-photothermal treatment. In addition, the pD coating strategy with simple procedures could address the contradiction between targeting modification and maintaining formerly excellent bio-properties. Therefore, with excellent bio-properties and simple preparation procedures, the DTX-loaded Apt-pD-CA-(PCL-ran-PLA) NPs effectively increased the local drug concentration in tumor sites, minimized side effects, and significantly eliminated tumors, indicating the promising application of these NPs for cancer therapy.

Clinically advancing and promising polymer-based therapeutics

In this review article, we will examine the history of polymers and their evolution from provisional World War II materials to medical therapeutics. To provide a comprehensive look at the current state of polymer-based therapeutics, we will classify technologies according to targeted areas of interest, including central nervous system-based and intraocular-, gastrointestinal-, cardiovascular-, dermal-, reproductive-, skeletal-, and neoplastic-based systems. Within each of these areas, we will consider several examples of novel, clinically available polymer-based therapeutics; in addition, this review will also include a discussion of developing therapies, ranging from the in vivo to clinical trial stage, for each targeted area of treatment. Finally, we will emphasize areas of patient care in need of more effective, accessible, and targeted treatment approaches where polymer-based therapeutics may offer potential solutions.

The combination of endolysosomal escape and basolateral stimulation to overcome the difficulties of "easy uptake hard transcytosis" of ligand-modified nanoparticles in oral drug delivery

Ligand-modified nanoparticles (NPs) are an effective tool to increase the endocytosis efficiency of drugs, but these functionalized NPs face the drawback of "easy uptake hard transcytosis" in the oral delivery of proteins and peptides. Adversely, the resulting deficiency in transcytosis has not attracted much attention. Herein, NPs modified with the low-density lipoprotein receptor (LDLR) ligand NH₂-C6-[cMPRLRGC]c-NH₂, i.e., peptide-22 (P22NPs) were fabricated to investigate strategies related to the enhancement of transcytosis. By systematically studying the intracellular trafficking of NPs, it was found that reduced transcytosis might be associated with the entrapment of P22NPs in endosomes or lysosomes and limited basolateral exocytosis. On this basis, the prevention of the endolysosomal entrapment of NPs and the acceleration of basolateral exocytosis should be considered as strategies to enhance the transcytosis of NPs. By screening chemicals that could help the endosomal/lysosomal escape of chemicals related to LDLR-mediated transcytosis, it was shown that hemagglutinin-2 (HA₂) and metformin had higher abilities to enhance the exocytosis of P22NPs. The transcytosis efficiencies of insulin loaded in P22NPs were also investigated, and a 3.2-fold increase in transcytosis was observed in comparison with free insulin. The transcytosis efficiencies of insulin could be further increased by the addition of metformin or HA₂ (3.6-fold or 4.1-fold higher than that of free insulin). Inspiringly, the simultaneous addition of the abovementioned two chemicals led to the highest transcytosis efficiency of insulin, which was up to 5.1-fold higher than that of free insulin. These results demonstrated that endolysosomal entrapment and basolateral exocytosis are two of the most important limiting steps for the "easy uptake hard transcytosis" of orally administered ligand-modified NPs. Moreover, our work provides a new point of view for the design of novel oral drug delivery systems.

Iron-mimic peptide converts transferrin from foe to friend for orally targeting insulin delivery

CRT-modified nanoparticles could effectively avoid the competitive inhibition of endogenous transferrin, and also convert an endogenous substance from foe to friend for active targeting.

Self-assembled nanomaterials for synergistic antitumour therapy

Recent progress on self-assembled nanodrugs for anticancer treatment was discussed.

A strategy for high radioprotective activity via the assembly of the PprI protein with a ROS-sensitive polymeric carrier

A strategy is developed for highly effective radioprotection with the PprI protein using a ROS-sensitive polymeric carrier.

Poly(ester amide)-based hybrid hydrogels for efficient transdermal insulin delivery

Transdermal drug delivery is an attractive, non-invasive treatment.

Cellular uptake of nanoparticles: journey inside the cell

Nanoscale materials are increasingly found in consumer goods, electronics, and pharmaceuticals. While these particles interact with the body in myriad ways, their beneficial and/or deleterious effects ultimately arise from interactions at the cellular and subcellular level. Nanoparticles (NPs) can modulate cell fate, induce or prevent mutations, initiate cell-cell communication, and modulate cell structure in a manner dictated largely by phenomena at the nano-bio interface. Recent advances in chemical synthesis have yielded new nanoscale materials with precisely defined biochemical features, and emerging analytical techniques have shed light on nuanced and context-dependent nano-bio interactions within cells. In this review, we provide an objective and comprehensive account of our current understanding of the cellular uptake of NPs and the underlying parameters controlling the nano-cellular interactions, along with the available analytical techniques to follow and track these processes.

Dendritic Mesoporous Silica Nanoparticles for pH-Stimuli-Responsive Drug Delivery of TNF-Alpha

Tumor necrosis factor-alpha (TNF-α) is a pleiotropic immune stimulatory cytokine and natural endotoxin that can induce necrosis and regression in solid tumors. However, systemic administration of TNF-α is not feasible due to its short half-life and acute toxicity, preventing its widespread use in cancer treatment. Dendritic mesoporous silica nanoparticles (DMSN) are used coated with a pH-responsive block copolymer gate system combining charged hyperbranched polyethylenimine and nonionic hydrophilic polyethylenglycol to encapsulate TNF-α and deliver it into various cancer cell lines and dendritic cells. Half-maximal effective concentration (EC₅₀ ) for loaded TNF-α is reduced by more than two orders of magnitude. Particle stability and premature cargo release are assessed with enzyme-linked immunosorbent assay. TNF-α-loaded particles are stable for up to 5 d in medium. Tumor cells are grown in vitro as 3D fluorescent ubiquitination-based cell cycle indicator spheroids that mimic in vivo tumor architecture and microenvironment, allowing real-time cell cycle imaging. DMSN penetrate these spheroids, release TNF-α from its pores, preferentially affect cells in S/G2/M phase, and induce cell death in a time- and dose-dependent manner. In conclusion, DMSN encapsulation is demonstrated, which is a promising approach to enhance delivery and efficacy of antitumor drugs, while minimizing adverse side effects.

Targeted nanoparticles for head and neck cancers: overview and perspectives

Head and neck cancer (HNC) is common in several regions and is associated with high morbidity and mortality worldwide. This review summarizes the recent progress in the development of targeted nanoparticle systems for HNC therapy. WIREs Nanomed Nanobiotechnol 2017, 9:e1469. doi: 10.1002/wnan.1469 For further resources related to this article, please visit the WIREs website.

Structure-Based Nanocarrier Design for Protein Delivery

Structure-based nanocarrier design for protein delivery remains challenging and has rarely been documented in the literature. We herein present a facile computer-aided approach for rational and customized design of a unique linear-dendritic telodendrimer that self-assembles into a nanocarrier for therapeutic protein delivery, e.g., insulin. Virtual screening of a small-molecule library was performed to identify optimal protein binding moieties, which were conjugated precisely in the telodendrimer backbone preinstalled with charged moieties. We systematically tested our hypothesis and obtained significant correlations between the computational predictions and experimental results. The d-α-tocopherol (vitamin E)-containing nanocarrier showed strong binding affinity for insulin in both computational prediction and experiments, which led to improved blood glucose control. This study affirms the concept and validates the approach of structure-based nanocarrier design for protein delivery.

pH-sensitive peptide hydrogel for glucose-responsive insulin delivery

Glucose-responsive system is one of important options for self-regulated insulin delivery to treat diabetes, which has become an issue of great public health concern in the world. In this study, we developed a novel and biocompatible glucose-responsive insulin delivery system using a pH-sensitive peptide hydrogel as a carrier loaded with glucose oxidase, catalase and insulin. The peptide could self-assemble into hydrogel under physiological conditions. When hypoglycemia is encountered, neighboring alkaline amino acid side chains are significantly repulsed due to reduced local pH by the enzymatic conversion of glucose into gluconic acid. This is followed by unfolding of individual hairpins, disassembly and release of insulin. The glucose-responsive hydrogel system was characterized on the basis of structure, conformation, rheology, morphology, acid-sensitivity and the amount of consistent release of insulin in vitro and vivo. The results illustrated that our system can not only regulate the blood glucose levels in vitro but also in mice models having STZ-induced diabetes.

STATEMENT OF SIGNIFICANCE

In this report, we have shown the following significance supported by the experimental results. 1. We successfully developed, characterized and screened a novel pH-responsive peptide. 2. We successfully developed a novel and biocompatible pH-sensitive peptide hydrogel as glucose-responsive insulin delivery system loaded with glucose oxidase, catalase and insulin. 3. We successfully confirmed that the hydrogel platform could regulate the blood glucose level in vitro and in vivo. Overall, we have shown enough significance and novelty with this smart hydrogel platform in terms of biomaterials, peptide chemistry, self-assembly, hydrogel and drug delivery. So we believe this manuscript is suitable for Acta Biomaterialia.

Enriching Nanoparticles via Acoustofluidics

Focusing and enriching submicrometer and nanometer scale objects is of great importance for many applications in biology, chemistry, engineering, and medicine. Here, we present an acoustofluidic chip that can generate single vortex acoustic streaming inside a glass capillary through using low-power acoustic waves (only 5 V is required). The single vortex acoustic streaming that is generated, in conjunction with the acoustic radiation force, is able to enrich submicrometer- and nanometer-sized particles in a small volume. Numerical simulations were used to elucidate the mechanism of the single vortex formation and were verified experimentally, demonstrating the focusing of silica and polystyrene particles ranging in diameter from 80 to 500 nm. Moreover, the acoustofluidic chip was used to conduct an immunoassay in which nanoparticles that captured fluorescently labeled biomarkers were concentrated to enhance the emitted signal. With its advantages in simplicity, functionality, and power consumption, the acoustofluidic chip we present here is promising for many point-of-care applications.

Cancer nanomedicine: progress, challenges and opportunities

The intrinsic limits of conventional cancer therapies prompted the development and application of various nanotechnologies for more effective and safer cancer treatment, herein referred to as cancer nanomedicine. Considerable technological success has been achieved in this field, but the main obstacles to nanomedicine becoming a new paradigm in cancer therapy stem from the complexities and heterogeneity of tumour biology, an incomplete understanding of nano-bio interactions and the challenges regarding chemistry, manufacturing and controls required for clinical translation and commercialization. This Review highlights the progress, challenges and opportunities in cancer nanomedicine and discusses novel engineering approaches that capitalize on our growing understanding of tumour biology and nano-bio interactions to develop more effective nanotherapeutics for cancer patients.

A strategy for developing effective orally-delivered nanoparticles through modulation of the surface “hydrophilicity/hydrophobicity balance”

Efficient oral delivery of macromolecules by nanoparticles is greatly limited by epithelial cells and the mucus layer that covers the surface of the intestinal epithelium.

Cancer nanomedicine: progress, challenges and opportunities

The intrinsic limits of conventional cancer therapies prompted the development and application of various nanotechnologies for more effective and safer cancer treatment, herein referred to as cancer nanomedicine. Considerable technological success has been achieved in this field, but the main obstacles to nanomedicine becoming a new paradigm in cancer therapy stem from the complexities and heterogeneity of tumour biology, an incomplete understanding of nano-bio interactions and the challenges regarding chemistry, manufacturing and controls required for clinical translation and commercialization. This Review highlights the progress, challenges and opportunities in cancer nanomedicine and discusses novel engineering approaches that capitalize on our growing understanding of tumour biology and nano-bio interactions to develop more effective nanotherapeutics for cancer patients.

Phenylboronic acid-incorporated elastin-like polypeptide nanoparticle drug delivery systems

Packaging hydrophobic drugs into nanoparticles can improve their aqueous solubility, tumor-specific accumulation and therapeutic effect.

CD20 monoclonal antibody targeted nanoscale drug delivery system for doxorubicin chemotherapy: an in vitro study of cell lysis of CD20-positive Raji cells

A monoclonal antibody targeted nanoscale drug delivery system (NDDS) for chemotherapy was evaluated in CD20-positive Raji cells in vitro. Nanoparticles were formed by the assembly of an amphiphilic polymer consisting of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxypolyethyleneglycol-2000 (DSPE-PEG2000). Active carbon nanoparticles (ACNP) were conjugated to the chemotherapeutic agent, doxorubicin (DOX), and the nanoliposome carrier, DSPE-PEG2000 and DSPE-PEG2000-NH₂ conjugated to the human anti-CD20 monoclonal antibody that targets B-lymphocytes. This monoclonal antibody targeted nanoparticle delivery system for chemotherapy formed the active NDDS complex, ACNP-DOX-DSPE-PEG2000-anti-CD20. This active NDDS was spherical in morphology and had good dispersion in the culture medium. When compared with the effects on CD20-negative YTS cells derived from natural killer/T-cell lymphoma, the active NDDS, ACNP-DOX-DSPE-PEG2000-anti-CD20, demonstrated DOX delivery to CD20-positive Raji cells derived from Burkitt’s lymphoma (B cell lymphoma), resulting in increased cell killing in vitro. The intracellular targeting efficiency of the ACNP-DOX-DSPE-PEG2000-anti-CD20 complex was assessed by confocal laser microscopy and flow cytometry. The findings of this in vitro study have shown that the DSPE-PEG2000 polymeric liposome is an effective nanocarrier of both a monoclonal antibody and a chemotherapy agent and can be used to target chemotherapy to specific cells, in this case to CD20-positive B-cells. Future developments in this form of targeted therapy will depend on the development of monoclonal antibodies that are specific for malignant cells, including antibodies that can distinguish between lymphoma cells and normal lymphocyte subsets.

Nanomedicines for renal disease: current status and future applications

Treatment and management of kidney disease currently presents an enormous global burden, and the application of nanotechnology principles to renal disease therapy, although still at an early stage, has profound transformative potential. The increasing translation of nanomedicines to the clinic, alongside research efforts in tissue regeneration and organ-on-a-chip investigations, are likely to provide novel solutions to treat kidney diseases. Our understanding of renal anatomy and of how the biological and physico-chemical properties of nanomedicines (the combination of a nanocarrier and a drug) influence their interactions with renal tissues has improved dramatically. Tailoring of nanomedicines in terms of kidney retention and binding to key membranes and cell populations associated with renal diseases is now possible and greatly enhances their localization, tolerability, and efficacy. This Review outlines nanomedicine characteristics central to improved targeting of renal cells and highlights the prospects, challenges, and opportunities of nanotechnology-mediated therapies for renal diseases.

Efficient Mini-Transporter for Cytosolic Protein Delivery

An efficient method to deliver active proteins into cytosol is highly desirable to advance protein-based therapeutics. Arginine-rich cell-penetrating peptides (RPPs) have been intensively studied for intracellular protein delivery, and their applications require further improvement on delivery efficiency, serum stability, and cytotoxicity. Designing synthetic analogs of RPPs provides an alternative way to achieve efficient cytosolic protein delivery. Herein we report the design and synthesis of a dendritic small molecule TG6, which is composed of one rigid planar core and four flexible arms with one guanidinium on each arm. Protein structure and function are well preserved in the TG6-protein conjugates, which are readily internalized into cytosol. Our study demonstrates that TG6 is a serum-stable and low-toxic molecular transporter delivering both small cargoes and large active proteins efficiently into cytosol.

Development of a reactive oxygen species (ROS)-responsive nanoplatform for targeted oral cancer therapy

In this study, for effective oral cancer therapy, a new targeted and ROS-triggered drug delivery nanoplatform was developed from the RGD-PEG-TK-PLGA polymer, in which the ROS-responsive TK containing linker was connected with PEG and PLGA. RGD in the drug delivery system (DDS) presented here was used to target cancer cells. This new nanoplatform shows high stability, good targeting ability, excellent ROS sensitivity and excellent biocompatibility. Loaded with DOX and alpha-TOS, the formulated nanoparticles (NPs) demonstrate much better cellular uptake efficiency and higher inhibition performance towards the oral tongue Cal27 cancer cell line. In vivo anticancer evaluation indicates that DOX and alpha-TOS loaded RGD-PEG-TK-PLGA NPs have no toxicity to mice and showed significantly improved therapeutic efficacy against tumors. Therefore, this polymeric NP platform presents great potential as a new DDS for oral cancer chemotherapy.