Particle replication in nonwetting templates nanoparticles with tumor selective alkyl silyl ether docetaxel prodrug reduces toxicity

Stimuli-Responsive Prodrug Chemistries for Cancer Therapy

Prodrugs are pharmacologically inactive, chemically modified derivatives of active drugs, which, following in vivo administration, are converted to the parent drugs through chemical or enzymatic cleavage. The prodrug approach holds tremendous potential to create the enhanced version of an existing pharmacological agent and leverage those improvements to augment the drug molecules' bioavailability, targeting ability, therapeutic efficacy, safety, and marketability. Especially in cancer therapy, prodrug application has received substantial attention. A prodrug can effectively broaden the therapeutic window of its parent drug by enhancing its release at targeted tumor sites while reducing its access to healthy cells. The spatiotemporally controlled release can be achieved by manipulating the chemical, physical, or biological stimuli present at the targeted tumor site. The critical strategy comprises drug-carrier linkages that respond to physiological or biochemical stimuli in the tumor milieu to yield the active drug form. This review will focus on the recent advancements in the development of various fluorophore-drug conjugates that are widely used for real-time monitoring of drug delivery. The use of different stimuli-cleavable linkers and the mechanisms of linker cleavage will be discussed. Finally, the review will conclude with a critical discussion of the prospects and challenges that might impede the future development of such prodrugs.

Targeted therapy of breast tumor by PLGA-based nanostructures: The versatile function in doxorubicin delivery

Breast carcinoma is a molecularly diverse illness, and it is among the most prominent and often reported malignancies in female across the globe. Surgical intervention, chemotherapy, immunotherapy, gene therapy, and endocrine treatment are among the currently viable treatment options for the carcinoma of breast. Chemotherapy is among the most prevalent cancer management strategy. Doxorubicin (DOX) widely employed as a cytostatic medication for the treatment of a variety of malignancies. Despite its widespread acceptance and excellent efficacy against an extensive line up of neoplasia, it has a variety of shortcomings that limit its therapeutic potential in the previously mentioned indications. Employment of nanoparticulate systems has come up as a unique chemo medication delivery strategy and are being considerably explored for the amelioration of breast carcinoma. Polylactic-co-glycolic acid (PLGA)-based nano systems are being utilized in a number of areas within the medical research and medication delivery constitutes one of the primary functions for PLGA given their inherent physiochemical attributes, including their aqueous solubility, biocompatibility, biodegradability, versatility in formulation, and limited toxicity. Herein along with the different application of PLGA-based nano formulations in cancer therapy, the present review intends to describe the various research investigations that have been conducted to enumerate the effectiveness of DOX-encapsulated PLGA nanoparticles (DOX-PLGA NPs) as a feasible treatment option for breast cancer.

Stimuli-Responsive Delivery Strategies for Controllable Gene Editing in Tumor Therapeutics

CRISPR system has attracted significant interest due to its great potential in tumour therapy. Developing effective, precise and safe delivery vectors is a prerequisite for CRISPR applications. Some disease-related biological...

Stimuli-responsive Polymeric nanosystems for therapeutic applications

BACKGROUND

Recent past decades have reported emerging of polymeric nanoparticles as a promising technique for controlled and targeted drug delivery. As nanocarriers, they have high drug loading and delivery to the specific site or targeted cells with an advantage of no drug leakage within en route and unloading of a drug in a sustained fashion at the site. These stimuli-responsive systems are functionalized in dendrimers, metallic nanoparticles, polymeric nanoparticles, liposomal nanoparticles, quantum dots.

PURPOSE OF REVIEW

The authors reviewed the potential of smart stimuli-responsive carriers for therapeutic application and their behavior in external or internal stimuli like pH, temperature, redox, light, and magnet. These stimuli-responsive drug delivery systems behave differently in In vitro and In vivo drug release patterns. Stimuli-responsive nanosystems include both hydrophilic and hydrophobic systems. This review highlights the recent development of the physical properties and their application in specific drug delivery.

CONCLUSION

The stimuli (smart, intelligent, programmed) drug delivery systems provide site-specific drug delivery with potential therapy for cancer, neurodegenerative, lifestyle disorders. As development and innovation, the stimuli-responsive based nanocarriers are moving at a fast pace and huge demand for biocompatible and biodegradable responsive polymers for effective and safe delivery.

"Plug and Play" Functionalized Erythrocyte Nanoplatform for Target Atherosclerosis Management

For atherosclerosis (AS) management, a therapeutic drug intervention is the most widely used strategy. However, there are some problems such as low location specificity, high intake, and side effects. Nanomedicine can prolong the half-life of drug solubilization, reduce toxic and side effects, and improve the distribution of drug objects. Herein, to overcome the challenges, an erythrocyte-based "plug and play" nanoplatform was developed by incorporating the vascular cell adhesion molecule-1 (VCAM-1) targeting and the acid stimulus responsibility. After the function moieties conjugated with DSPE-PEG, the targeting peptide and the acid-sensitive prodrug were conveniently integrated into red blood cells' surface for enhancing target AS drug delivery and controlling local drug release. As a proof of principle, a plug and play nanoplatform with targeted drug delivery and acid-control drug release is demonstrated, achieving a marked therapeutic effect for AS.

Stimulus-cleavable chemistry in the field of controlled drug delivery

This review comprehensively summarises stimulus-cleavable linkers from various research areas and their cleavage mechanisms, thus provides an insightful guideline to extend their potential applications to controlled drug release from nanomaterials.

Novel octapeptide-DTX prodrugs targeting MMP-7 as effective agents for the treatment of colorectal cancer with lower systemic toxicity

Colorectal cancer (CRC) is the third most common cancer and the fourth leading cause of cancer death around the world. The current treatments of CRC exhibited high occurrence rate of side effects. Docetaxel (DTX), an important drug widely used in cancer chemotherapy, showed serious toxicity in CRC. Reducing toxicity of DTX could be a feasible and promising way to achieve the new indication of DTX for CRC. In this study, a series of MMP-7 activated octapeptide-DTX/4FDT prodrugs (6a-10a and 6b-10b) were designed and synthesized based on the features of MMP-7 which is highly expressed in CRC and could specially recognize octapeptides with specific sequences. Among them, 9a and 9b, both possessing an octapeptide Gly-Pro-Gln-Gly-Ile-Ala-Met-Gln moiety, were the most potent prodrugs. Compounds 9a and 9b were also tested their release rate in HCT116 cell culture fluids and tumor homogenate along with in vivo anti-CRC activity and systemic toxicity. Since 9a showed better anti-CRC activity and lower systemic toxicity than 9b in CRC tumor bearing mice, it was further evaluated for its acute toxicity, pharmacokinetics and tissue distribution in comparison with its parent drug DTX. These results revealed that 9a possessed good systemic stability, rapid release rate in CRC and reduced systemic toxicity, while retaining similar anti-CRC activity to its parent drug DTX. Thus, 9a, an MMP-7 polypeptide prodrug of DTX, has been identified as a promising candidate for the treatment of CRC.

SERCA and P-glycoprotein inhibition and ATP depletion are necessary for celastrol-induced autophagic cell death and collateral sensitivity in multidrug-resistant tumor cells

Multidrug resistance (MDR) represents an obstacle in anti-cancer therapy. MDR is caused by multiple mechanisms, involving ATP-binding cassette (ABC) transporters such as P-glycoprotein (P-gp), which reduces intracellular drug levels to sub-therapeutic concentrations. Therefore, sensitizing agents retaining effectiveness against apoptosis- or drug-resistant cancers are desired for the treatment of MDR cancers. The sarcoplasmic/endoplasmic reticulum Ca²⁺ ATPase (SERCA) pump is an emerging target to overcome MDR, because of its continuous expression and because the calcium transport function is crucial to the survival of tumor cells. Previous studies showed that SERCA inhibitors exhibit anti-cancer effects in Bax-Bak-deficient, apoptosis-resistant and MDR cancers, whereas specific P-gp inhibitors reverse the MDR phenotype of cancer cells by blocking efflux of chemotherapeutic agents. Here, we unraveled SERCA and P-gp as double targets of the triterpenoid, celastrol to reverse MDR. Celastrol inhibited both SERCA and P-gp to stimulate calcium-mediated autophagy and ATP depletion, thereby induced collateral sensitivity in MDR cancer cells. In vivo studies further confirmed that celastrol suppressed tumor growth and metastasis by SERCA-mediated calcium mobilization. To the best of our knowledge, our findings demonstrate collateral sensitivity in MDR cancer cells by simultaneous inhibition of SERCA and P-gp for the first time.

pH- and enzyme-triggered drug release as an important process in the design of anti-tumor drug delivery systems

It is necessary to design a reasonable drug delivery system(DDS) for targeted release to overcome the potential toxicity and poor selectivity of anti-tumor drug. How a drug is released from a DDS is a critical issue that determines whether the DDS is designed successfully. We all know that the microenvironment of tumors is quite different from normal tissues, such as its acidic environment, different expression levels of some enzymes, etc. These features are widely used in the design of DDSs and play an important role in the drug release process in vivo. Numerous DDSs have been designed and synthesized. This article attention to how drugs are released from DDSs. We summarizes and classify the characteristic enzymes and chemical bonds used in the drug release process by browsing a large number of papers, and describes how they are applied in DDSs with specific examples. By understanding these acid-sensitive chemical bonds and over-expressed enzymes in tumors, different DDSs can be designed for different drug structures to solve specific problems of anti-tumor drugs.

Novel Silyl Ether-Based Acid-Cleavable Antibody-MMAE Conjugates with Appropriate Stability and Efficacy

Antibody-drug conjugate (ADC) is a novel efficient drug delivery system that has been successfully used in clinical practice, and it has become a research hotspot in the anti-tumor drug field. Acid-cleavable linkers were first used in clinical ADCs, but their structural variety (e.g., hydrazone and carbonate) is still limited, and their stability is usually insufficient. Designing novel acid-cleavable linkers for the conjugation of the popular cytotoxin monomethyl auristatin E (MMAE) has always been a significant topic. In this paper, we generate a novel, silyl ether-based acid-cleavable antibody-MMAE conjugate, which skillfully achieves efficient combination of amino-conjugated MMAE with the acid-triggered silyl ether group by introducing p-hydroxybenzyl alcohol (PHB). The stability, acid-dependence cleavage, effective mechanism, efficacy and safety of the resulting ADC were systematically studied; the results show that it exhibits a significant improvement in stability, while maintaining appropriate efficacy and controlled therapeutic toxicity. This strategy is expected to expand a new type of acid-cleavable linkers for the development of ADCs with highly potent payloads.

Efficient synthesis of tetrazole hemiaminal silyl ethers via three-component hemiaminal silylation

An efficient route to construct 2,5-disubstituted tetrazole hemiaminal silyl ethers via one-pot three-component hemiaminal silylation of 5-substituted tetrazoles, aldehydes, and silyl triflates was developed. Diverse 2,5-disubstituted tetrazole hemiaminal silyl ethers were obtained with 37 : 63->99 : 1 regioisomeric ratios. The regioselectivities of this reaction were significantly affected by steric hindrance and the conjugation effects of substitutions on the 5-position of tetrazoles.

Machine Learning Approach for Determining the Formation of β-Lactam Antibiotic Complexes with Cyclodextrins Using Multispectral Analysis

The problem of determining the formation of complexes of β-lactam antibiotics with cyclodextrins (CDs) and the interactions involved in this process were addressed by machine learning on multispectral images. Complexes of β-lactam antibiotics, including cefuroxime axetil, cefetamet pivoxil, and pivampicillin, as well as CDs, including αCD, βCD, γCD, hydroxypropyl-αCD, methyl-βCD, hydroxypropyl-βCD, and hydroxypropyl-γCD, were prepared in all combinations. Thermograms confirming the formation of cyclodextrin complexes were obtained using differential scanning calorimetry. Transmission Fourier-transform infrared (tFTIR) and complementary attenuated total reflectance FTIR (ATR) coupled with machine learning were techniques chosen as a nondestructive alternative. The machine learning algorithm was used to determine the formation of complexes in samples using solely their tFTIR and ATR spectra at the prediction stage. Parameterized method 7 (PM7) was used to support the analysis by molecular modeling of the complexes. The model developed through machine learning properly distinguished samples with formed complexes form noncomplexed samples with a cross-validation accuracy of 90.4%. Analysis of the contribution of spectral bands to the model indicated interactions of ester groups of β-lactam antibiotics with CDs, as well as some interactions of cephem ring in cefetamet pivoxil and penam moiety in pivampicillin. Molecular modeling with PM7 helped to explain experimental results and allowed to propose possible binding modes.

Zapped assembly of polymeric (ZAP) nanoparticles for anti-cancer drug delivery

The starting hypothesis for this work was that microwave synthesis could enable the rapid assembly of polymers into size-specific nanoparticles (NPs). The Zapped Assembly of Polymeric (ZAP) NPs was initially realized using poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) block copolymers and distinct microwave reaction parameters. A library of polymeric NPs was generated with sizes ranging from sub-20 nm to 350 nm and low polydispersity. Select ZAP NPs were synthesized in 30 seconds at different scales and concentrations, up to 200 mg and 100 mg mL-1, without substantial size variation. ZAP NPs with diameters of 25 nm, 50 nm, and 100 nm were loaded with the chemotherapeutic paclitaxel (PXL), demonstrated unique release profiles, and exhibited dose-dependent cytotoxicity similar to Taxol. Incorporation of d-alpha tocopheryl polyethylene glycol succinate (TPGS) and PLGA33k allowed for the production of a sub-40 nm NP with an exceptionally high loading of PXL (12.6 wt%, ca. 7 times the original NP) and a slower release profile. This ZAP NP platform demonstrated scalable, flexible, and tunable synthesis with potential toward clinical scale production of size-specific drug carriers.

Anisotropic biodegradable lipid coated particles for spatially dynamic protein presentation

There has been growing interest in the use of particles coated with lipids for applications ranging from drug delivery, gene delivery, and diagnostic imaging to immunoengineering. To date, almost all particles with lipid coatings have been spherical despite emerging evidence that non-spherical shapes can provide important advantages including reduced non-specific elimination and increased target-specific binding. We combine control of core particle geometry with control of particle surface functionality by developing anisotropic, biodegradable ellipsoidal particles with lipid coatings. We demonstrate that these lipid coated ellipsoidal particles maintain advantageous properties of lipid polymer hybrid particles, such as the ability for modular protein conjugation to the particle surface using versatile bioorthogonal ligation reactions. In addition, they exhibit biomimetic membrane fluidity and demonstrate lateral diffusive properties characteristic of natural membrane proteins. These ellipsoidal particles simultaneously provide benefits of non-spherical particles in terms of stability and resistance to non-specific phagocytosis by macrophages as well as enhanced targeted binding. These biomaterials provide a novel and flexible platform for numerous biomedical applications.

STATEMENT OF SIGNIFICANCE

The research reported here documents the ability of non-spherical polymeric particles to be coated with lipids to form anisotropic biomimetic particles. In addition, we demonstrate that these lipid-coated biodegradable polymeric particles can be conjugated to a wide variety of biological molecules in a "click-like" fashion. This is of interest due to the multiple types of cellular mimicry enabled by this biomaterial based technology. These features include mimicry of the highly anisotropic shape exhibited by cells, surface presentation of membrane bound protein mimetics, and lateral diffusivity of membrane bound substrates comparable to that of a plasma membrane. This platform is demonstrated to facilitate targeted cell binding while being resistant to non-specific cellular uptake. Such a platform could allow for investigations into how physical parameters of a particle and its surface affect the interface between biomaterials and cells, as well as provide biomimetic technology platforms for drug delivery and cellular engineering.

Docetaxel-Loaded PLGA Nanoparticles Improve Efficacy in Taxane-Resistant Triple-Negative Breast Cancer

Novel treatment strategies, including nanomedicine, are needed for improving management of triple-negative breast cancer. Patients with triple-negative breast cancer, when considered as a group, have a worse outcome after chemotherapy than patients with breast cancers of other subtypes, a finding that reflects the intrinsically adverse prognosis associated with the disease. The aim of this study was to improve the efficacy of docetaxel by incorporation into a novel nanoparticle platform for the treatment of taxane-resistant triple-negative breast cancer. Rod-shaped nanoparticles encapsulating docetaxel were fabricated using an imprint lithography based technique referred to as Particle Replication in Nonwetting Templates (PRINT). These rod-shaped PLGA-docetaxel nanoparticles were tested in the C3(1)-T-antigen (C3Tag) genetically engineered mouse model (GEMM) of breast cancer that represents the basal-like subtype of triple-negative breast cancer and is resistant to therapeutics from the taxane family. This GEMM recapitulates the genetics of the human disease and is reflective of patient outcome and, therefore, better represents the clinical impact of new therapeutics. Pharmacokinetic analysis showed that delivery of these PLGA-docetaxel nanoparticles increased docetaxel circulation time and provided similar docetaxel exposure to tumor compared to the clinical formulation of docetaxel, Taxotere. These PLGA-docetaxel nanoparticles improved tumor growth inhibition and significantly increased median survival time. This study demonstrates the potential of nanotechnology to improve the therapeutic index of chemotherapies and rescue therapeutic efficacy to treat nonresponsive cancers.

Efficacy and pharmacokinetics of a modified acid-labile docetaxel-PRINT(®) nanoparticle formulation against non-small-cell lung cancer brain metastases

AIM

Particle Replication in Nonwetting Templates (PRINT(®)) PLGA nanoparticles of docetaxel and acid-labile C2-dimethyl-Si-Docetaxel were evaluated with small molecule docetaxel as treatments for non-small-cell lung cancer brain metastases.

MATERIALS & METHODS

Pharmacokinetics, survival, tumor growth and mice weight change were efficacy measures against intracranial A549 tumors in nude mice. Treatments were administered by intravenous injection.

RESULTS

Intracranial tumor concentrations of PRINT-docetaxel and PRINT-C2-docetaxel were 13- and sevenfold greater, respectively, than SM-docetaxel. C2-docetaxel conversion to docetaxel was threefold higher in intracranial tumor as compared with nontumor tissues. PRINT-C2-docetaxel increased median survival by 35% with less toxicity as compared with other treatments.

CONCLUSION

The decreased toxicity of the PRINT-C2-docetaxel improved treatment efficacy against non-small-cell lung cancer brain metastasis.

Co-opting Moore's law: Therapeutics, vaccines and interfacially active particles manufactured via PRINT®

Nanoparticle properties such as size, shape, deformability, and surface chemistry all play a role in nanomedicine drug delivery. While many studies address the behavior of particle systems in a biological setting, revealing how these properties work together presents unique challenges on the nanoscale. Particle replication in non-wetting templates (PRINT®) is one molding technique that allows for fabrication of "calibration quality" micro and nanoparticles with independent control over their physical parameters. As the only technology in the world capable of independently optimizing and robustly manufacturing GMP compliant precision particles of virtually any size, shape, and composition, the PRINT technology has the capability to engineer the future of healthcare.

Shaping the future of nanomedicine: anisotropy in polymeric nanoparticle design

Nanofabrication and biomedical applications of polymeric nanoparticles have become important areas of research. Biocompatible polymeric nanoparticles have been investigated for their use as delivery vehicles for therapeutic and diagnostic agents. Although polymeric nanoconstructs have traditionally been fabricated as isotropic spheres, anisotropic, nonspherical nanoparticles have gained interest in the biomaterials community owing to their unique interactions with biological systems. Polymeric nanoparticles with different forms of anisotropy have been manufactured using a variety of novel methods in recent years. In addition, they have enhanced physical, chemical, and biological properties compared with spherical nanoparticles, including increased targeting avidity and decreased nonspecific in vivo clearance. With these desirable properties, anisotropic nanoparticles have been successfully utilized in many biomedical settings and have performed superiorly to analogous spherical nanoparticles. We summarize the current state-of-the-art fabrication methods for anisotropic polymeric nanoparticles including top-down, bottom-up, and microfluidic design approaches. We also summarize the current and potential future applications of these nanoparticles, including drug delivery, biological targeting, immunoengineering, and tissue engineering. Ongoing research into the properties and utility of anisotropic polymeric nanoparticles will prove critical to realizing their potential in nanomedicine.

Targeted PRINT Hydrogels: The Role of Nanoparticle Size and Ligand Density on Cell Association, Biodistribution, and Tumor Accumulation

In this Letter, we varied targeting ligand density of an EGFR binding affibody on the surface of two different hydrogel PRINT nanoparticles (80 nm × 320 and 55 nm × 60 nm) and monitored effects on target-cell association, off-target phagocytic uptake, biodistribution, and tumor accumulation. Interestingly, variations in ligand density only significantly altered in vitro internalization rates for the 80 nm × 320 nm particle. However, in vivo, both particle sizes experienced significant changes in biodistribution and pharmacokinetics as a function of ligand density. Overall, nanoparticle size and passive accumulation were the dominant factors eliciting tumor sequestration.

Polymeric nanoparticles: the future of nanomedicine

Polymeric nanoparticles (NPs) are one of the most studied organic strategies for nanomedicine. Intense interest lies in the potential of polymeric NPs to revolutionize modern medicine. To determine the ideal nanosystem for more effective and distinctly targeted delivery of therapeutic applications, particle size, morphology, material choice, and processing techniques are all research areas of interest. Utilizations of polymeric NPs include drug delivery techniques such as conjugation and entrapment of drugs, prodrugs, stimuli-responsive systems, imaging modalities, and theranostics. Cancer, neurodegenerative disorders, and cardiovascular diseases are fields impacted by NP technologies that push scientific boundaries to the leading edge of transformative advances for nanomedicine.

Biomimetic particles as therapeutics

In recent years, there have been major advances in the development of novel nanoparticle- and microparticle-based therapeutics. An emerging paradigm is the incorporation of biomimetic features into these synthetic therapeutic constructs to enable them to better interface with biological systems. Through the control of size, shape, and material consistency, particle cores have been generated that better mimic natural cells and viruses. In addition, there have been significant advances in biomimetic surface functionalization of particles through the integration of bio-inspired artificial cell membranes and naturally derived cell membranes. Biomimetic technologies enable therapeutic particles to have increased potency to benefit human health.

Biodistribution and Toxicity Studies of PRINT Hydrogel Nanoparticles in Mosquito Larvae and Cells

Mosquito-borne diseases continue to remain major threats to human and animal health and impediments to socioeconomic development. Increasing mosquito resistance to chemical insecticides is a great public health concern, and new strategies/technologies are necessary to develop the next-generation of vector control tools. We propose to develop a novel method for mosquito control that employs nanoparticles (NPs) as a platform for delivery of mosquitocidal dsRNA molecules to silence mosquito genes and cause vector lethality. Identifying optimal NP chemistry and morphology is imperative for efficient mosquitocide delivery. Toward this end, fluorescently labeled polyethylene glycol NPs of specific sizes, shapes (80 nm x 320 nm, 80 nm x 5000 nm, 200 nm x 200 nm, and 1000 nm x 1000 nm) and charges (negative and positive) were fabricated by Particle Replication in Non-Wetting Templates (PRINT) technology. Biodistribution, persistence, and toxicity of PRINT NPs were evaluated in vitro in mosquito cell culture and in vivo in Anopheles gambiae larvae following parenteral and oral challenge. Following parenteral challenge, the biodistribution of the positively and negatively charged NPs of each size and shape was similar; intense fluorescence was observed in thoracic and abdominal regions of the larval body. Positively charged NPs were more associated with the gastric caeca in the gastrointestinal tract. Negatively charged NPs persisted through metamorphosis and were observed in head, body and ovaries of adults. Following oral challenge, NPs were detected in the larval mid- and hindgut. Positively charged NPs were more efficiently internalized in vitro than negatively charged NPs. Positively charged NPs trafficked to the cytosol, but negatively charged NPs co-localized with lysosomes. Following in vitro and in vivo challenge, none of the NPs tested induced any cytotoxic effects.

Preparation and biological evaluation of synthetic and polymer-encapsulated congeners of the antitumor agent pactamycin: insight into functional group effects and biological activity

The synthesis and biological analysis of a number of novel congeners of the aminocyclopentitol pactamycin is described. Specific attention was paid to the preparation of derivatives at crucial synthetic branch points of the parent structure, and biological assays revealed a number of insights into the source of pactamycin's biological activity. Additionally, the encapsulation of pactamycin and select derivatives into the PRINT© nanoparticle technology was investigated as a proof-of-concept, and evidence of bioactivity modulation through nanoparticle delivery is demonstrated. This work has provided heretofore unrealized access to a large number of novel compounds for further evaluation.

An automated multidimensional thin film stretching device for the generation of anisotropic polymeric micro- and nanoparticles

Anisotropic polymeric particles are of growing interest for biomaterials applications due to their unique properties. These include the ability for these particles to evade nonspecific cellular uptake and to have enhanced targeted cellular uptake and interaction. One of the most widely used methods for generating anisotropic polymeric particles is the thin film stretching procedure. Despite its theoretical simplicity, this procedure, as it has been implemented to date, can be difficult due to the inconsistent nature of the manual operation of machinery used to stretch the film. We have constructed an automated thin film stretcher for control over biomaterials via thin film stretching in 1D and 2D and as a result, have enabled precise generation of anisotropic polymeric particles. We demonstrate that this device can be utilized to produce anisotropic biodegradable particles of different size, shape, and material consistency. Furthermore, we show that this machine has enabled the scaled up and rapid production of anisotropic polymeric particles, including polymeric microparticles that mimic the shape of red blood cells. Further application of this automated thin film stretching device could allow for significant impact to diverse biomaterial and biomedical applications such as biomimetic particles for immunoengineering and long-circulating particles for controlled release of drugs.

Calibration-quality cancer nanotherapeutics

Nanoparticle properties such as size, shape, deformability, and surface chemistry all play a role in nanomedicine drug delivery in cancer. While many studies address the behavior of particle systems in a biological setting, revealing how these properties work together presents unique challenges on the nanoscale. "Calibration-quality" control over such properties is needed to draw adequate conclusions that are independent of parameter variability. Furthermore, active targeting and drug loading strategies introduce even greater complexities via their potential to alter particle pharmacokinetics. Ultimately, the investigation and optimization of particle properties should be carried out in the appropriate preclinical tumor model. In doing so, translational efficacy improves as clinical tumor properties increase. Looking forward, the field of nanomedicine will continue to have significant clinical impacts as the capabilities of nanoparticulate drug delivery are further enhanced.

Nanoparticle Delivery Systems Reduce the Reproductive Toxicity of Docetaxel in Rodents

Various docetaxel (DTX)-loaded nanoparticle delivery systems have been designed to enhance the solubility and pharmacological effects of DTX. However, the toxicity changes of these nano-modified DTX (nano-DTX) are not yet clear enough. Herein, to compare the reproductive toxicity between conventional DTX and nano-DTX, we performed sperm toxicity test in mice, and fertility and early embryo-fetal developmental toxicity test in rats. It was found that DTX severely repressed spermatogenesis and sperm motility, and dramatically increased sperm abnormality in mice and rats. Moreover, DTX significantly decreased copulation, conception and fertility indexes in rats, and no positive pregnant female rat was obtained after treatment with DTX. However, nano-DTX significantly reduced DTX-induced toxicity to sperm. Most importantly, nano-DTX obviously converted DTX-induced fertility and early embryo-fetal developmental toxicity. Furthermore, organ weights and histopathology examination revealed DTX, but not nano-DTX, significantly decreased testis and epididymis weights, and induced obvious histopathological atrophy of testes and epididymides in rats. Further studies indicated that changed activity of lactate dehydrogenase C4 (LDH-C4) in rodents testes was mainly responsible for the above observations. These results strongly support the idea that DTX-loaded nanoformulations have the potential to overcome the reproductive toxicity of DTX.

Prodrug-based nanoparticulate drug delivery strategies for cancer therapy

Despite the rapid developments in nanotechnology and biomaterials, the efficient delivery of chemotherapeutic agents is still challenging. Prodrug-based nanoassemblies have many advantages as a potent platform for anticancer drug delivery, such as improved drug availability, high drug loading efficiency, resistance to recrystallization upon encapsulation, and spatially and temporally controllable drug release. In this review, we discuss prodrug-based nanocarriers for cancer therapy, including nanosystems based on polymer-drug conjugates, self-assembling small molecular weight prodrugs and prodrug-encapsulated nanoparticles (NPs). In addition, we discuss new trends in the field of prodrug-based nanoassemblies that enhance the delivery efficiency of anticancer drugs, with special emphasis on smart stimuli-triggered drug release, hybrid nanoassemblies, and combination drug therapy.

Synthesis of Acid-Labile PEG and PEG-Doxorubicin-Conjugate Nanoparticles via Brush-First ROMP

A panel of acid-labile bis-norbornene cross-linkers was synthesized and evaluated for the formation of acid-degradable brush-arm star polymers (BASPs) via the brush-first ring-opening metathesis polymerization (ROMP) method. An acetal-based cross-linker was identified that, when employed in conjunction with a poly(ethylene glycol) (PEG) macromonomer, provided highly controlled BASP formation reactions. A combination of this new cross-linker with a novel doxorubicin (DOX)-branch-PEG macromonomer provided BASPs that simultaneously degrade and release cytotoxic DOX in vitro.

A versatile acid-labile linker for antibody–drug conjugates

Silyl ether chemistry was used as the linker for an antibody drug conjugate to release a chemotherapeutic at low pH.