Ultrasonic delivery of silica–gold nanoshells for photothermolysis of sebaceous glands in humans: Nanotechnology from the bench to clinic

Microchanneling and ultrasonic delivery of gold and platinum nanoparticles for selective photothermolysis of sebaceous follicles in the treatment of acne: a pilot study using porcine skin

PURPOSE

Several treatment options for acne vulgaris are limited by their associated adverse effects. An innovative approach involves introducing light-absorbing nanoparticles into sebaceous follicles before destroying the follicles using selective photothermolysis. We aimed to investigate efficient methods for introducing gold and platinum nanoparticles into sebaceous follicles and to identify suitable laser equipment and parameters for the effective destruction of these follicles.

METHODS

We used porcine skin as the experimental model. We compared the efficacies of a thulium laser, ultrasound, and manual massage and evaluated the optimal method for delivering nanoparticles in close proximity to sebaceous follicles. Subsequently, a 1064-nm-wavelength neodymium-doped yttrium aluminum garnet (Nd: YAG) laser was employed to induce selective photothermolysis. We compared different parameters to identify the optimal pulse duration and fluence of the Nd: YAG laser. The extent of penetration and destruction of sebaceous follicles was assessed using hematoxylin and eosin (H&E) staining, and a numerical evaluation was conducted.

RESULTS

H&E staining showed that irradiation with a long-pulsed Nd: YAG laser following a combination of thulium laser and sonophoresis effectively destroyed sebaceous follicles, with destruction rates exceeding 50%. These results were valid with a long pulse duration and a high fluence of the Nd: YAG laser.

CONCLUSION

This study demonstrated that sebaceous follicles can be effectively destroyed through a mixture of gold and platinum nanoparticle delivery by a combination of microchanneling and sonophoresis, followed by selective thermal damage induced by a 1064-nm long-pulsed high-fluence Nd: YAG laser.

Hair Follicle-Targeted Delivery of Azelaic Acid Micro/Nanocrystals Promote the Treatment of Acne Vulgaris

Purpose

Acne vulgaris is a chronic inflammatory skin disorder centered on hair follicles, making hair follicle-targeted delivery of anti-acne drugs a promising option for acne treatment. However, current researches have only focused on the delivering to healthy hair follicles, which are intrinsically different from pathologically clogged hair follicles in acne vulgaris.

Patients and Methods

Azelaic acid (AZA) micro/nanocrystals with different particle sizes were prepared by wet media milling or high-pressure homogenization. An experiment on AZA micro/nanocrystals delivering to healthy hair follicles was carried out, with and without the use of physical enhancement techniques. More importantly, it innovatively designed an experiment, which could reveal the ability of AZA micro/nanocrystals to penetrate the constructed clogged hair follicles. The anti-inflammatory and antibacterial effects of AZA micro/nanocrystals were evaluated in vitro using a RAW264.7 cell model stimulated by lipopolysaccharide and a Cutibacterium acnes model. Finally, both the anti-acne effects and skin safety of AZA micro/nanocrystals and commercial products were compared in vivo.

Results

In comparison to commercial products, 200 nm and 500 nm AZA micro/nanocrystals exhibited an increased capacity to target hair follicles. In the combination group of AZA micro/nanocrystals and ultrasound, the ability to penetrate hair follicles was further remarkably enhanced (ER value up to 9.6). However, toward the clogged hair follicles, AZA micro/nanocrystals cannot easily penetrate into by themselves. Only with the help of 1% salicylic acid, AZA micro/nanocrystals had a great potential to penetrate clogged hair follicle. It was also shown that AZA micro/nanocrystals had anti-inflammatory and antibacterial effects by inhibiting pro-inflammatory factors and Cutibacterium acnes. Compared with commercial products, the combination of AZA micro/nanocrystals and ultrasound exhibited an obvious advantage in both skin safety and in vivo anti-acne therapeutic efficacy.

Conclusion

Hair follicle-targeted delivery of AZA micro/nanocrystals provided a satisfactory alternative in promoting the treatment of acne vulgaris.

Electrosprayable Levan-Coated Nanoclusters and Ultrasound-Responsive Drug Delivery for Cancer Therapy

In this study, we synthesized levan shell hydrophobic silica nanoclusters encapsulating doxorubicin (L-HSi-Dox) and evaluated their potential as ultrasound-responsive drug delivery systems for cancer treatment. L-HSi-Dox nanoclusters were successfully fabricated by integrating a hydrophobic silica nanoparticle-doxorubicin complex as the core and an amphiphilic levan carbohydrate polymer as the shell by using an electrospray technique. Characterization analyses confirmed the stability, size, and composition of the nanoclusters. In particular, the nanoclusters exhibited a controlled release of Dox under aqueous conditions, demonstrating their potential as efficient drug carriers. The levanic groups of the nanoclusters enhanced the targeted delivery of Dox to specific cancer cells. Furthermore, the synergism between the nanoclusters and ultrasound effectively reduced cell viability and induced cell death, particularly in the GLUT5-overexpressing MDA-MB-231 cells. In a tumor xenograft mouse model, treatment with the nanoclusters and ultrasound significantly reduced the tumor volume and weight without affecting the body weight. Collectively, these results highlight the potential of the L-HSi-Dox nanoclusters and ultrasound as promising drug delivery systems with an enhanced therapeutic efficacy for biomedical applications.

Applications and safety of gold nanoparticles as therapeutic devices in clinical trials

Use of gold nanoparticles (GNPs) in medicine is an emerging field of translational research with vast clinical implications and exciting therapeutic potential. However, the safety of using GNPs in human subjects is an important question that remains unanswered. This study reviews over 20 clinical trials focused on GNP safety and aims to summarize all the clinical studies, completed and ongoing, to identify whether GNPs are safe to use in humans as a therapeutic platform. In these studies, GNPs were implemented as drug delivery devices, for photothermal therapy, and utilized for their intrinsic therapeutic effects by various routes of delivery. These studies revealed no major safety concerns with the use of GNPs; however, the number of trials and total patient number remains limited. Multi-dose, multi-center blinded trials are required to deepen our understanding of the use of GNPs in clinical settings to facilitate translation of this novel, multifaceted therapeutic device. Expanding clinical trials will require collaboration between clinicians, scientists, and biotechnology companies.

Current progress of mesenchymal stem cell membrane-camouflaged nanoparticles for targeted therapy

Nanodrug delivery systems have been widely used in disease treatment. However, weak drug targeting, easy to be cleared by the immune system, and low biocompatibility are great obstacles for drug delivery. As an important part of cell information transmission and behavior regulation, cell membrane can be used as drug coating material which represents a promising strategy and can overcome these limitations. Mesenchymal stem cell (MSC) membrane, as a new carrier, has the characteristics of active targeting and immune escape of MSC, and has broad application potential in tumor treatment, inflammatory disease, tissue regeneration and other fields. Here, we review recent progress on the use of MSC membrane-coated nanoparticles for therapy and drug delivery, aiming to provide guidance for the design and clinical application of membrane carrier in the future.

Clinical translation of gold nanoparticles

Gold nanoparticles display unique physicochemical features, which can be useful for therapeutic purposes. After two decades of preclinical progress, gold nanoconstructs are slowly but steadily transitioning into clinical trials. Although initially thought to be "magic golden bullets" that could be used to treat a wide range of diseases, current consensus has moved toward a more realistic approach, where gold nanoformulations are being investigated to treat specific disorders. These therapeutic applications are dictated by the pharmacokinetics and biodistribution profiles of gold nanoparticles. Here, we analyze the current clinical landscape of therapeutic gold nanoconstructs, discuss the shared characteristics that allowed for their transition from bench to bedside, and examine existing hurdles that need to be overcome before they can be approved for clinical use.

Photothermal therapy using gold nanoparticles and a long-pulsed 755-nm alexandrite laser to treat facial photoaging in Asian skin: A prospective clinical trial

BACKGROUND AND OBJECTIVES

Transdermally delivered gold nanoparticles (AuNPs) irradiated with near-infrared laser energy can create a photothermal effect within the sebaceous glands (SGs). Photothermal therapy (PTT) can be used clinically to reverse photoaging in SG-rich areas of the skin. Improvements in wrinkles and enlarged pores in Asian skin were assessed following AuNP-mediated PTT with a long-pulsed 755-nm alexandrite laser.

STUDY DESIGN/MATERIALS AND METHODS

A single-arm, prospective trial was designed. Twenty Korean patients underwent three gold PTT interventions performed 4 weeks apart at laser hair-removal settings without cooling. At Week 20, changes in the wrinkle index (WI) and pore index (PI), size, and count were calculated using three-dimensional camera analyses. Overall improvements in wrinkles and pores (0-4 scale) were assessed by blinded investigators using standardized photographic comparisons. The subjects scored their satisfaction (0-10 scale) and treatment discomfort (0-10 scale). Safety data were also collected.

RESULTS

There were significant reductions in the WI (8.3%, p < 0.01), pore size (23.1%, p = 0.035), and PI (19.9%, p = 0.034) in the periorbital areas at week 20 compared with baseline. The mean reductions in the size (22.5%, p = 0.027), count (16.5%, p = 0.048), and index (22.4%, p = 0.023) of the cheek pores were also significant. Investigators reported average scores of 3.2 ± 0.6 for improved wrinkle appearance, and 3.1 ± 0.7 for improvement in visible pores. Participants were moderately satisfied with the overall results (7.6 ± 1.8). Subjects felt moderate discomfort during treatment (4.7 ± 2.6). No serious or persistent adverse events occurred.

CONCLUSIONS

AuNP-mediated PTT showed noticeable efficacy and tolerability in treating wrinkles and pores in Asian skin over a 12 week-follow-up. Further studies with a longer follow-up are needed to confirm the reduction in SG activity at the parameters used.

Multifunctional Gold Nanoparticles for Improved Diagnostic and Therapeutic Applications: A Review

The medical properties of metals have been explored for centuries in traditional medicine for the treatment of infections and diseases and still practiced to date. Platinum-based drugs are the first class of metal-based drugs to be clinically used as anticancer agents following the approval of cisplatin by the United States Food and Drug Administration (FDA) over 40 years ago. Since then, more metals with health benefits have been approved for clinical trials. Interestingly, when these metals are reduced to metallic nanoparticles, they displayed unique and novel properties that were superior to their bulk counterparts. Gold nanoparticles (AuNPs) are among the FDA-approved metallic nanoparticles and have shown great promise in a variety of roles in medicine. They were used as drug delivery, photothermal (PT), contrast, therapeutic, radiosensitizing, and gene transfection agents. Their biomedical applications are reviewed herein, covering their potential use in disease diagnosis and therapy. Some of the AuNP-based systems that are approved for clinical trials are also discussed, as well as the potential health threats of AuNPs and some strategies that can be used to improve their biocompatibility. The reviewed studies offer proof of principle that AuNP-based systems could potentially be used alone or in combination with the conventional systems to improve their efficacy.

Nanotechnology-based formulations toward the improved topical delivery of anti-acne active ingredients

Introduction: Acne vulgaris is a chronic inflammatory skin disorder that affects an extremely concerning percentage of teenagers (ca. 85%), gathering serious negative impacts on the social life and psychological well-being of individuals. Conventional topical formulations for acne show low tolerability and side effects, such as skin irritation, leading to a decrease in the user's adherence to therapy. Nanotechnology-based formulations were developed as new strategies for topical acne management, particularly to overcome the difficulties associated with conventional treatments.Areas covered: This paper presents a critical analysis of reviewed nanosized anti-acne technological strategies, strongly supporting controlled active ingredient release, improved skin permeation, and lower skin irritation. An updated regulatory framework, considering the promising applications in nanomedicine, and the toxicity of these nanosystems are also addressed.Expert opinion: Nanosystems evidence several advantages, attending to the possibility of controlled active ingredient release, better skin permeation, and lower skin irritation. However, novel nanotechnological strategies for acne treatment and care can lead to new side effects, but also environmental nano pollution. Little is known about the toxicology of these nanotechnology-based formulations, therefore, as future trends, more studies should be conducted to assure the consumers' health and environmental safety.

Photothermal therapy using gold nanoparticles for acne in Asian patients: A preliminary study

Acne is a common skin disease that occurs in pilosebaceous units and is often prevalent in adolescence. There are many acne treatments, but they are associated with side effects, such as antibiotic resistance, teratogenicity, and irritation. Therefore, it is necessary to develop a more effective and safe alternative treatment for managing acne in patients of all ages. This study aimed to confirm the effect of gold photothermal therapy for acne. About 12 patients who visited the dermatologic clinic with moderate to severe acne vulgaris were included in the study, regardless of age or sex. All patients received three successive treatments at 1- to 2-week intervals with a photopneumatic device after applying the contents of a gold nanoparticle ample to the skin. Changes in the number of papules, pustules, and comedones before and after treatment, along with the overall improvement, were assessed. In four patients, a biopsy was taken before and 1 month after the last treatment. Significant reductions in acne lesions were observed after the use of gold photothermal therapy (papules, P = .001; pustules, P < .001; and comedones, P = .001). As noted in the Physician Global Assessment, the patients showed an average improvement of more than 50% in their condition. In the histopathological findings, a decrease in inflammatory cell infiltration and fibrotic changes of the dermis were observed after gold photothermal therapy. Gold photothermal therapy showed significant clinical and histological improvements in acne vulgaris in Asians without serious adverse effects.

Subclinical effects of adapalene-benzoyl peroxide: a prospective in vivo imaging study on acne micromorphology and transfollicular delivery

BACKGROUND

Adapalene-benzoyl peroxide (A-BPO) is a first-line topical treatment for acne vulgaris. In vivo reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) detect micromorphological changes over time and visualize transfollicular delivery.

OBJECTIVES

To visualize temporal, subclinical effects of A-BPO on acne micromorphology using RCM and OCT, and evaluate their impact on transfollicular delivery of microparticulate carrier systems.

METHODS

Fifteen patients with mild to moderate acne received a 6-week course of A-BPO. Micromorphological changes were evaluated at time 0, 3 and 6 weeks with RCM (n = 1190 images) and OCT (n = 210 scans). Transfollicular delivery of microparticles was assessed at baseline and week 6.

RESULTS

In vivo imaging visualized steady normalization of skin micromorphology in response to A-BPO over 6 weeks, including decreased hyperkeratinization of follicular borders (RCM median decrease -71.2%, P < 0.05), reduced intrafollicular keratinous content (RCM median decrease -47.7%, P < 0.05) and increased epidermal thickness (OCT median increase of 25.25%, P < 0.05). Imaging visualized microparticles in the follicular unit. Despite a visible reduction in keratin and sebum, transfollicular microparticle delivery appeared unaffected.

CONCLUSIONS

Reflectance confocal microscopy and OCT detect A-BPO-induced changes in micromorphology and visualize transfollicular microparticle delivery. Keratolysis and sebolysis did not have a measurable effect on transfollicular delivery of microparticles.

Label-Free Visualization and Tracking of Gold Nanoparticles in Vasculature Using Multiphoton Luminescence

Gold nanoparticles continue to generate interest for use in several biomedical applications. Recently, researchers have been focusing on exploiting their dual diagnostic/therapeutic theranostic capabilities. Before clinical translation can occur, regulatory agencies will require a greater understanding of their biodistribution and safety profiles post administration. Previously, the real-time identification and tracking of gold nanoparticles in free-flowing vasculature had not been possible without extrinsic labels such as fluorophores. Here, we present a label-free imaging approach to examine gold nanoparticle (AuNP) activity within the vasculature by utilizing multiphoton intravital microscopy. This method employs a commercially available multiphoton microscopy system to visualize the intrinsic luminescent signal produced by a multiphoton absorption-induced luminescence effect observed in single gold nanoparticles at frame rates necessary for capturing real-time blood flow. This is the first demonstration of visualizing unlabeled gold nanoparticles in an unperturbed vascular environment with frame rates fast enough to achieve particle tracking. Nanoparticle blood concentration curves were also evaluated by the tracking of gold nanoparticle flow in vasculature and verified against known pre-injection concentrations. Half-lives of these gold nanoparticle injections ranged between 67 and 140 s. This label-free imaging approach could provide important structural and functional information in real time to aid in the development and effective analysis of new metallic nanoparticles for various clinical applications in an unperturbed environment, while providing further insight into their complex uptake and clearance pathways.

Advanced nanomedicines for the treatment of inflammatory diseases

Inflammation, a common feature of many diseases, is an essential immune response that enables survival and maintains tissue homeostasis. However, in some conditions, the inflammatory process becomes detrimental, contributing to the pathogenesis of a disease. Targeting inflammation by using nanomedicines (i.e. nanoparticles loaded with a therapeutic active principle), either through the recognition of molecules overexpressed onto the surface of activated macrophages or endothelial cells, or through enhanced vasculature permeability, or even through biomimicry, offers a promising solution for the treatment of inflammatory diseases. After providing a brief insight on the pathophysiology of inflammation and current therapeutic strategies, the review will discuss, at a pre-clinical stage, the main innovative nanomedicine approaches that have been proposed in the past five years for the resolution of inflammatory disorders, finally focusing on those currently in clinical trials.

Bio-inspired apatite particles limit skin penetration of drugs for dermatology applications

Most treatments of skin pathologies involve local administration of active agents. One issue can however be the partial transcutaneous diffusion of the drug to blood circulation, leading to undesirable effects. In this work, the original use of submicron mineral particles based on bio-inspired calcium phosphate apatite was explored for the first time as drug carriers for favoring topical delivery. The permeation of a model drug across synthetic and biological membranes was investigated in both static and dynamic conditions. Our data show that adsorption of the drug on the apatite particles surface drastically limits its permeation, with lower effective diffusion coefficients (P_eff) and smaller total released amounts. The retention of the apatite colloidal particles on porcine ear skin explants surface was demonstrated by combining histological observations and Raman confocal microscopy. All results converge to show that association of the drug to apatite particles favors skin surface effects. These findings point to the relevance of mineral-based particles as drug carriers for local delivery to the skin, and open the way to novel applications of bio-inspired apatites in dermatology. STATEMENT OF SIGNIFICANCE: Calcium phosphates (CaP) are major biomaterials in orthopedics and dentistry. Their resemblance to bone mineral allows new applications beyond bone repair, e.g. in nanomedicine. In 2018, a 14-page detailed review (M. Epple, Acta Biomaterialia 77 (2018) 1-14) provided clear facts in favor of the non-toxicity of nanosized CaP as an answer to discussions from EU and US study groups, thus clarifying the path to novel applications of nano CaP. In the present paper, bio-inspired apatite nanoparticles are used for the first time as drug carriers for dermatology for drastically limiting drug transcutaneous permeation and retaining a topical effect. We demonstrate this proof of concept via permeation cell tests, histology, Raman microscopy and photoluminescence after application on porcine ear skin.

Adaptive changes induced by noble-metal nanostructures in vitro and in vivo

The unique features of noble-metal nanostructures (NMNs) are leading to unprecedented expansion of research and exploration of their application in therapeutics, diagnostics and bioimaging fields. With the ever-growing applications of NMNs, both therapeutic and environmental NMNs are likely to be exposed to tissues and organs, requiring careful studies towards their biological effects in vitro and in vivo. Upon NMNs exposure, tissues and cells may undergo a series of adaptive changes both in morphology and function. At the cellular level, the accumulation of NMNs in various subcellular organelles including lysosomes, endoplasmic reticulum, Golgi apparatus, mitochondria, and nucleus may interfere with their functions, causing changes in a variety of cellular functions, such as digestion, protein synthesis and secretion, energy metabolism, mitochondrial respiration, and proliferation. In animals, retention of NMNs in metabolic-, respiratory-, immune-related, and other organs can trigger significant physiological and pathological changes to these organs and influence their functions. Exploring how NMNs interact with tissues and cells and the underlying mechanisms are of vital importance for their future applications. Here, we illustrate the characteristics of NMNs-induced adaptive changes both in vitro and in vivo. Potential strategies in the design of NMNs are also discussed to take advantage of beneficial adaptive changes and avoid unfavorable changes for the proper implementation of these nanoplatforms.

Dye-doped silica nanoparticles: synthesis, surface chemistry and bioapplications

Background

Fluorescent silica nanoparticles have been extensively utilised in a broad range of biological applications and are facilitated by their predictable, well-understood, flexible chemistry and apparent biocompatibility. The ability to couple various siloxane precursors with fluorescent dyes and to be subsequently incorporated into silica nanoparticles has made it possible to engineer these fluorophores-doped nanomaterials to specific optical requirements in biological experimentation. Consequently, this class of nanomaterial has been used in applications across immunodiagnostics, drug delivery and human-trial bioimaging in cancer research.

Main body

This review summarises the state-of-the-art of the use of dye-doped silica nanoparticles in bioapplications and firstly accounts for the common nanoparticle synthesis methods, surface modification approaches and different bioconjugation strategies employed to generate biomolecule-coated nanoparticles. The use of dye-doped silica nanoparticles in immunoassays/biosensing, bioimaging and drug delivery is then provided and possible future directions in the field are highlighted. Other non-cancer-related applications involving silica nanoparticles are also briefly discussed. Importantly, the impact of how the protein corona has changed our understanding of NP interactions with biological systems is described, as well as demonstrations of its capacity to be favourably manipulated.

Conclusions

Dye-doped silica nanoparticles have found success in the immunodiagnostics domain and have also shown promise as bioimaging agents in human clinical trials. Their use in cancer delivery has been restricted to murine models, as has been the case for the vast majority of nanomaterials intended for cancer therapy. This is hampered by the need for more human-like disease models and the lack of standardisation towards assessing nanoparticle toxicity. However, developments in the manipulation of the protein corona have improved the understanding of fundamental bio–nano interactions, and will undoubtedly assist in the translation of silica nanoparticles for disease treatment to the clinic.

Nanoparticles for topical drug delivery: Potential for skin cancer treatment

Nanoparticles offer new opportunities for the treatment of skin diseases. The barrier function of the skin poses a significant challenge for nanoparticles to permeate into the tissue, although the barrier is partially compromised in case of injury or inflammation, as in the case of skin cancer. This may facilitate the penetration of nanoparticles. Extensive research has gone into developing nanoparticles for topical delivery; however, relatively little progress has been made in translating them to the clinic for treating skin cancers. We summarize the types of skin cancers and practices in current clinical management. The review provides a comprehensive outlook of the various nanoparticle technologies tested for topical therapy of skin cancers and summarizes the obstacles that impede its progress from the bench-to-bedside. The review also aims to provide an understanding of the pathways that govern nanoparticle penetration into the skin and a critical analysis of the approaches used to study nanoparticle interactions within the tissue.

Gold nanoshell-mediated photothermal therapy for acne vulgaris

Acne vulgaris, a common and chronic disorder of the pilosebaceous unit, affects up to 85% of adolescent and young adults. Although the current treatment options are effective, they are associated with unwanted side effects, chronicity, relapses, and recurrences. Recently, the Food and Drug Administration approved topical application of gold microparticles for selective photothermolysis to treat acne vulgaris. Here, we report two cases showing the efficacy of gold nanoshell-mediated photothermal therapy for recurrent acne that were refractory to previous treatments. In both cases, three sessions of photothermal therapy prevented the development of new lesions during a follow-up period of 3-4 months without causing any adverse effects. The two cases reported here demonstrate the possibility of gold nanoshell-mediated photothermal therapy as a safe and effective treatment for recurrent acne vulgaris in Asian patients.

In Vivo Reflectance Confocal Microscopy of Gold Microparticles Deposited in the Skin. A Case Report on Cutaneous Chrysiasis

Cutaneous chrysiasis is gold deposition in the dermis, described after parenteral administration of gold salts or after topical exposure to gold-containing materials. Gold microparticles (GMPs) have versatile therapeutic effects and are increasingly used in medicine. This case report describes the development of a blue-gray macule following the facial application of GMPs and laser treatment of acne vulgaris. Dermoscopy showed a nonspecific homogenous blue-gray pattern, gradually fading over an 8-month-period. Reflectance confocal microscopy (RCM) detected hyperreflective, subcellular particles in the papillary dermis, localized around hair follicles, eccrine glands, and inside macrophages. Histopathological evaluation, darkfield illumination with hyperspectral imaging, and neutron activation analysis confirmed the presence of GMPs in the dermis. RCM allowed non-invasive fast visualization of aggregates of hyperreflective particles in the dermis and can potentially be used for monitoring localized cutaneous chrysiasis and other metal deposition conditions over time. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Gold nanomaterials as key suppliers in biological and chemical sensing, catalysis, and medicine

BACKGROUND

Gold nanoparticles (AuNPs) with unique physicochemical properties have received a great deal of interest in the field of biological, chemical and biomedical implementations. Despite the widespread use of AuNPs in chemical and biological sensing, catalysis, imaging and diagnosis, and more recently in therapy, no comprehensive summary has been provided to explain how AuNPs could aid in developing improved sensing and catalysts systems as well as medical settings.

SCOPE OF REVIEW

The chemistry of Au-based nanosystems was followed by reviewing different applications of Au nanomaterials in biological and chemical sensing, catalysis, imaging and diagnosis by a number of approaches, and finally synergistic combination therapy of different cancers. Afterwards, the clinical impacts of AuNPs, future application of AuNPs, and opportunities and challenges of AuNPs application were also discussed.

MAJOR CONCLUSIONS

AuNPs show exclusive colloidal stability and are considered as ideal candidates for colorimetric detection, catalysis, imaging, and photothermal transducers, because their physicochemical properties can be tuned by adjusting their structural dimensions achieved by the different manufacturing methods.

GENERAL SIGNIFICANCE

This review provides some details about using AuNPs in sensing and catalysis applications as well as promising theranostic nanoplatforms for cancer imaging and diagnosis, and sensitive, non-invasive, and synergistic methods for cancer treatment in an almost comprehensive manner.

Transfollicular delivery of gold microparticles in healthy skin and acne vulgaris, assessed by in vivo reflectance confocal microscopy and optical coherence tomography

INTRODUCTION

Topical application of gold microparticles (GMPs) for selective photothermolysis is a recently FDA-cleared therapy for acne vulgaris. Current evidence indicates the potential of optical imaging to non-invasively visualize GMPs and describe photothermal tissue effects.

OBJECTIVES

To qualitatively and quantitatively describe GMP delivery in vivo and visualize laser-mediated thermal effects of GMPs in facial skin of acne patients and healthy participants, using reflectance confocal microscopy (RCM) and optical coherence tomography (OCT).

METHODS

Patients with facial acne (n = 14), and healthy participants (n = 7) were included. RCM and OCT images were acquired at baseline, after GMP application, and after diode laser exposure. All images were evaluated qualitatively and quantitatively with regards to GMP delivery in skin layers and morphological thermal effects. Lastly, skin biopsies were obtained to compare RCM and OCT findings to histology.

RESULTS

GMPs were delivered equally in healthy participants and acne patients, and in lesional and non-lesional acne skin. In RCM images, GMPs appeared as hyperreflective aggregates inside hair follicles and eccrine ducts, corresponding to natural skin openings (NSOs). The fraction of NSOs with hyperreflective content increased significantly after GMP application compared to baseline (50-75% increase, P = 8.88 × 10-16 ). Similarly, in OCT images, GMPs appeared as hyperreflective columns inside hair follicles and were not detected in surrounding skin. GMPs reached a maximum depth of 920 μm (median 300 μm). After laser exposure, RCM and histology revealed selective perifollicular tissue changes around NSOs.

CONCLUSION

Optical imaging visualizes GMP delivery and thermal tissue response following laser exposure and enables bedside monitoring of transfollicular microparticle delivery. Lasers Surg. Med. 51:430-438, 2019. © 2019 Wiley Periodicals, Inc.

Functional Mesoporous Silica Nanocomposites: Biomedical applications and Biosafety

The rise and development of nanotechnology has enabled the creation of a wide number of systems with new and advantageous features to treat cancer. However, in many cases, the lone application of these new nanotherapeutics has proven not to be enough to achieve acceptable therapeutic efficacies. Hence, to avoid these limitations, the scientific community has embarked on the development of single formulations capable of combining functionalities. Among all possible components, silica-either solid or mesoporous-has become of importance as connecting and coating material for these new-generation therapeutic nanodevices. In the present review, the most recent examples of fully inorganic silica-based functional composites are visited, paying particular attention to those with potential biomedical applicability. Additionally, some highlights will be given with respect to their possible biosafety issues based on their chemical composition.

Heat transfer from nanoparticles for targeted destruction of infectious organisms

Whereas the application of optically or magnetically heated nanoparticles to destroy tumours is now well established, the extension of this concept to target pathogens has barely begun. Here we examine the challenge of targeting pathogens by this means and, in particular, explore the issues of power density and heat transfer. Depending on the rate of heating, either hyperthermia or thermoablation may occur. This division of the field is fundamental and implies very different sources of excitation and heat transfer for the two modes, and different strategies for their clinical application. Heating by isolated nanoparticles and by agglomerates of nanoparticles is compared: hyperthermia is much more readily achieved with agglomerates and for large target volumes, a factor which favours magnetic excitation and moderate power densities. In contrast, destruction of planktonic pathogens is best achieved by localised thermoablation and very high power density, a scenario that is best delivered by pulsed optical excitation.

Advances in the treatment of traumatic scars with laser, intense pulsed light, radiofrequency, and ultrasound

Traumatic scarring is one of the most common complications after soft tissue injury caused by burns and trauma, which affects tens of millions of people worldwide every year. Traumatic scars diminish the quality of life due to disfigurement, symptoms of pain and itch, and restricted motion. The pathogenesis and pathophysiology of traumatic scar remain elusive. The management for traumatic scars is comprised of surgical and non-surgical interventions such as pressure therapy, silicone, corticosteroid, and radiotherapy, which are chosen by clinicians based on the physical examinations of scars. Recently, great progress in treating traumatic scars has been achieved by the development of novel technologies including laser, intense pulsed light (IPL), radiofrequency, and ultrasound. The aim of this review article was to summarize the advances of these technologies for traumatic scars intervention.

A repertoire of biomedical applications of noble metal nanoparticles

The emerging properties of noble metal nanoparticles are attracting huge interest from the translational scientific community. In this feature article, we highlight recent advances in the adaptation of noble metal nanomaterials and their biomedical applications in therapeutics, diagnostics and sensing.

Porous Inorganic Carriers Based on Silica, Calcium Carbonate and Calcium Phosphate for Controlled/Modulated Drug Delivery: Fresh Outlook and Future Perspectives

Porous inorganic nanostructured materials are widely used nowadays as drug delivery carriers due to their adventurous features: suitable architecture, large surface area and stability in the biological fluids. Among the different types of inorganic porous materials, silica, calcium carbonate, and calcium phosphate have received significant attention in the last decade. The use of porous inorganic materials as drug carriers for cancer therapy, gene delivery etc. has the potential to improve the life expectancy of the patients affected by the disease. The main goal of this review is to provide general information on the current state of the art of synthesis of the inorganic porous particles based on silica, calcium carbonate and calcium phosphate. Special focus is dedicated to the loading capacity, controllable release of drugs under internal biological stimuli (e.g., pH, redox, enzymes) and external noninvasive stimuli (e.g., light, magnetic field, and ultrasound). Moreover, the diverse compounds to deliver with silica, calcium carbonate and calcium phosphate particles, ranging from the commercial drugs to genetic materials are also discussed.

Modeling gold nanoparticle biodistribution after arterial infusion into perfused tissue: effects of surface coating, size and protein corona

A detailed understanding of the factors governing nanomaterial biodistribution is needed to rationally design safe nanomedicines. This research details the pharmacokinetics of gold nanoparticle (AuNP) biodistribution after arterial infusion of 40 or 80 nm AuNP (1 μg/ml) into the isolated perfused porcine skin flap (IPPSF). AuNP had surface coatings consisting of neutral polyethylene glycol (PEG), anionic lipoic acid (LA), or cationic branched polyethylenimine (BPEI). Effect of a porcine plasma corona (PPC) on 40 nm BPEI and PEG-AuNP were assessed in the IPPSF. Au concentrations were determined by ICP/MS and arterial to venous concentration-time profiles were analyzed over 8 hr (4 hr infusion, 4 hr washout) using a two-compartment pharmacokinetic model. IPPSF viability and vascular function were assessed by change in glucose utilization, vascular resistance, or weight gain after perfusion. All AuNP demonstrated some degree of AuNP arterial extraction and skin flap retention, as well as enhanced kinetic parameters of tissue uptake; with BPEI-AuNP consistently having the greatest biodistribution even with a PPC. Toxicological effects were not detected. Transmission electron microscopy confirmed intracellular uptake of AuNP. These studies paralleled previous in vitro cell culture studies using the same AuNP in human endothelial and renal proximal tubule cells, hepatocytes, keratinocytes, showing BPEI-AuNP having the greatest uptake, although the presence of a PPC did not reduce IPPSF biodistribution as in the cell culture studies. These findings clearly indicate arterial to the venous extraction of AuNP after infusion with the magnitude of extraction being greatest with the BPEI surface coating and provide data and model structure necessary to construct the whole body physiologically based pharmacokinetic models capable of utilizing available in vitro data.

Energy-Based Devices in Treatment of Acne Vulgaris

BACKGROUND

Acne vulgaris is a chronic dermatologic complaint with a multifactorial cause. Traditionally, antibiotics and retinoids have been used to manage the condition; patient compliance has been an ongoing issue. A variety of energy-based devices have been reported to be effective in the treatment of acne vulgaris.

OBJECTIVE

To review and summarize the current literature specific to treatment of acne vulgaris with energy-based devices.

METHODS

A review of the current literature of energy-based devices used for the treatment of acne vulgaris.

RESULTS AND CONCLUSIONS

Although limited randomized controlled trials for the treatment of acne have been performed, significant clinical improvement of acne vulgaris, especially of inflammatory lesions, has been demonstrated with a variety of energy-based devices. Newer approaches may lead to even better results.

Preparation of an antimicrobial surface by direct assembly of antimicrobial peptide with its surface binding activity

The designed antimicrobial peptide has surface binding activity onto titanium, gold, polymethyl methacrylate and hydroxyapatite substrates.

Lipase-Sensitive Transfersomes Based on Photosensitizer/Polymerizable Lipid Conjugate for Selective Antimicrobial Photodynamic Therapy of Acne

Acne vulgaris is a common skin problem affecting nearly 90% of adolescents and its development is associated with a colonization of Propionibacterium acnes (P. acnes). Although antibiotics have commonly been used to treat acne, antibiotic resistance of P. acnes is an emerging issue to be solved. In this study, a new way of photodynamic acne therapy is developed using P. acnes lipase-sensitive transfersome (DSPE-PEG-Pheo A (DPP) transfersome). For enhanced selectivity and skin penetration efficiency, DPP transfersomes are prepared from 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000], pheophorbide A (Pheo A), cholesterol, and Tween-80. Incorporation of Tween-80 as an edge activator increases the deformability of DPP transfersomes, enhancing skin penetration efficiency to four times that of free Pheo A. The photoactivity of Pheo A quenched by DPP transfersomes is gradually recovered by selective cleavage of the ester linkage in DPP transfersomes by P. acnes lipases. In vitro P. acnes-specific photoactivity and subsequent selective antimicrobial effect exhibit a greater than 99% loss of P. acnes viability. In vivo antiacne therapeutic effect is confirmed by reduction of swelling volume and thickness of P. acnes-induced nude mice skin. These results demonstrate that DPP transfersome-mediated photodynamic therapy can be used as an alternative method to treat bacterial skin infections.

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.

Proretinal nanoparticles: stability, release, efficacy, and irritation

Despite many potent biological activities, retinoids such as retinoic acid (RA) and retinal possess dose-related broad side effects. In this study, we show that this problem, which has been unsolvable for a long time, can be tackled through a controlled release strategy in which retinal is continuously delivered to the skin via sustained release from proretinal nanoparticles. The water dispersible proretinal nanoparticles are stable when kept in water at neutral pH and at room temperature for 8 months under light-proof conditions, and show sustained release of retinal into human synthetic sebum at a pH of 5. In the daily topical application tests performed for 4 weeks on rats' skin, the nanoparticles showed superior ability to increase epidermal thickness compared to RA and retinal, with no skin irritation observed for the proretinal particles, but severe skin irritation observed for RA and free retinal. When tested under occlusion conditions in human volunteers, insignificant skin irritation was observed for the proretinal nanoparticles. The 12-week, double-blind, split-face study on human volunteers indicates better antiaging efficacy of the particles as compared to the free RA.

A Review of Clinical Translation of Inorganic Nanoparticles

Inorganic nanoparticles are widely used for therapeutic and diagnostic purposes as they offer unique features as compared with their organic and polymeric counterparts. As such, inorganic nanoparticles represent an exciting opportunity to develop drug delivery and imaging systems that are poised to tackle unique challenges which are currently unaddressed in clinical settings. Despite these clear advantages, very few inorganic nanoparticle systems have entered the clinic. Here, we review the current clinical landscape of inorganic nanoparticle systems and their opportunities and challenges, with particular emphasis on gold-, iron-oxide- and silica-based nanoparticle systems. Key examples of inorganic nanoparticles that are currently being investigated in the clinic (e.g., trials which are recruiting or currently active but not completed) are highlighted, along with the preclinical work that these examples have leveraged to transition from the lab to the clinic.

Accelerating the Translation of Nanomaterials in Biomedicine

Due to their size and tailorable physicochemical properties, nanomaterials are an emerging class of structures utilized in biomedical applications. There are now many prominent examples of nanomaterials being used to improve human health, in areas ranging from imaging and diagnostics to therapeutics and regenerative medicine. An overview of these examples reveals several common areas of synergy and future challenges. This Nano Focus discusses the current status and future potential of promising nanomaterials and their translation from the laboratory to the clinic, by highlighting a handful of successful examples.

A Review of Clinical Translation of Inorganic Nanoparticles

Inorganic nanoparticles are widely used for therapeutic and diagnostic purposes as they offer unique features as compared with their organic and polymeric counterparts. As such, inorganic nanoparticles represent an exciting opportunity to develop drug delivery and imaging systems that are poised to tackle unique challenges which are currently unaddressed in clinical settings. Despite these clear advantages, very few inorganic nanoparticle systems have entered the clinic. Here, we review the current clinical landscape of inorganic nanoparticle systems and their opportunities and challenges, with particular emphasis on gold-, iron-oxide- and silica-based nanoparticle systems. Key examples of inorganic nanoparticles that are currently being investigated in the clinic (e.g., trials which are recruiting or currently active but not completed) are highlighted, along with the preclinical work that these examples have leveraged to transition from the lab to the clinic.