Near-infrared inorganic nanomaterial-based nanosystems for photothermal therapy

Black porous silicon as a photothermal agent and immunoadjuvant for efficient antitumor immunotherapy

Photothermal therapy (PTT) in combination with other treatment modalities has shown great potential to activate immunotherapy against tumor metastasis. However, the nanoparticles (NPs) that generate PTT have served as the photothermal agent only. Moreover, researchers have widely utilized highly immunogenic tumor models to evaluate the immune response of these NPs thus giving over-optimistic results. In the present study black porous silicon (BPSi) NPs were developed to serve as both the photothermal agent and the adjuvant for PTT-based antitumor immunotherapy. We found that the poorly immunogenic tumor models such as B16 are more valid to evaluate NP-based immunotherapy than the widely used immunogenic models such as CT26. Based on the B16 cancer model, a cocktail regimen was developed that combined BPSi-based PTT with doxorubicin (DOX) and cytosine-phosphate-guanosine (CpG). BPSi-based PTT was an important trigger to activate the specific immunotherapy to inhibit tumor growth by featuring the selective upregulation of TNF-α. Either by adding a low dose DOX or by prolonging the laser heating time, a similar efficacy of immunotherapy was evoked to inhibit tumor growth. Moreover, BPSi acted as a co-adjuvant for CpG to significantly boost the immunotherapy. The present study demonstrates that the BPSi-based regimen is a potent and safe antitumor immunotherapy modality. Moreover, our study highlighted that tuning the laser heating parameters of PTT is an alternative to the toxic cytostatic to evoke immunotherapy, paving the way to optimize the PTT-based combination therapy for enhanced efficacy and decreased side effects. STATEMENT OF SIGNIFICANCE: Tumor metastasis causes directly or indirectly more than 90% of cancer deaths. Combination of photothermal therapy (PTT), chemotherapy and immunotherapy based on nanoparticles (NPs) has shown great potential to inhibit distant and metastatic tumors. However, these NPs typically act only as photothermal agents and many of them have been evaluated with immunogenic tumor models. The present study developed black porous silicon working as both the photothermal conversion agent and the immunoadjuvant to inhibit distant tumor. It was recognized that the poorly immunogenic tumor model B16 is more appropriate to evaluate immunotherapy than the widely used immunogenic model CT26. The coordination mechanism of the PTT-based combination therapy regimen was discovered in detail, paving the way to optimize cancer immunotherapy for enhanced efficacy and decreased side effects.

Growth of ZIF-8 Nanoparticles In Situ on Graphene Oxide Nanosheets: A Multifunctional Nanoplatform for Combined Ion-Interference and Photothermal Therapy

The regulation of intracellular ions' overload to interrupt normal bioprocesses and cause cell death has been developed as an efficient strategy (named as ion-interference therapy/IIT) to treat cancer. In this study, we design a multifunctional nanoplatform (called BSArGO@ZIF-8 NSs) by in situ growth of metal organic framework nanoparticles (ZIF-8 NPs) onto the graphene oxide (GO) surface, subsequently reduced by ascorbic acid and modified by bovine serum albumin. This nanocomplex causes the intracellular overload of Zn²⁺, an increase of reactive oxygen species (ROS), and exerts a broad-spectrum lethality to different kinds of cancer cells. BSArGO@ZIF-8 NSs can promote cell apoptosis by initiating bim (a pro-apoptotic protein)-mediated mitochondrial apoptotic events, up-regulating PUMA/NOXA expression, and down-regulating the level of Bid/p53AIP1. Meanwhile, Zn²⁺ excess triggers cellular dysfunction and mitochondria damage by activating the autophagy signaling pathways and disturbing the intracellular environmental homeostasis. Combined with the photothermal effect of reduced GO (rGO), BSArGO@ZIF-8 NSs mediated ion-interference and photothermal combined therapy leads to effective apoptosis and inhibits cell proliferation and angiogenesis, bringing a higher efficacy in tumor suppression in vivo. This designed Zn-based multifunctional nanoplatform will allow promoting further the development of IIT and the corresponding combined cancer therapy strategy.

Nitrogen-doped carbon dots/curcumin nanocomposite for combined Photodynamic/photothermal dual-mode antibacterial therapy

Due to their excellent photophysical properties, carbon quantum dots have great potential in biomedical and drug delivery fields. In this study, nitrogen-doped carbon quantum dots with good water solubility were prepared using citric acid and ethylenediamine as precursors, and compounded with curcumin, a photosensitive component, to produce composite nanomaterials with photodynamic therapy and synergistic photothermal therapy. The formation of nitrogen-doped carbon quantum dots and composite nanomaterials was verified using physical and optical means. In addition, the composite nanomaterials produced single-linear oxygen and exacerbated the increase of solution temperature under blue (405 nm) and near-infrared (808 nm) light irradiation, respectively. The plate counting method showed that the composite nanomaterials exhibited good photodynamic synergistic photothermal antibacterial properties against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus under dual light source (405+808 nm) irradiation, which improved the photoinactivation of curcumin against bacteria. In addition, the composite nanomaterials exhibited low toxicity and good hemocompatibility. These experimental results suggested that the composite nanomaterials showed great potential in a multimodal photodynamic therapy synergistic photothermal treatment platform.

Escherichia coli Mimetic Gold Nanorod-Mediated Photo- and Immunotherapy for Treating Cancer and Its Metastasis

Most cancer-related deaths are due to metastasis or recurrence. Therefore, the ultimate goal of cancer therapy will be to treat metastatic and recurrent cancers. Combination therapy for cancer will be one of trial for effective treating metastasis and recurrence. In this study, Escherichia coli-mimetic nanomaterials are synthesized using Escherichia coli membrane proteins, adhesion proteins, and gold nanorods, which are named E. coli mimetic AuNRs (ECA), for combination therapy against cancer and its recurrence. ECA treatment with 808 nm laser irradiation eliminates CT-26 or 4T1 tumors via a photothermal effect. ECA with laser irradiation induces activation of immune cells in the tumor-draining lymph nodes. The mice cured from CT-26 or 4T1 tumor by ECA are rechallenged with those cancer in the lung metastatic form, and the results showed that ECA treatment for the first CT-26 or 4T1 tumor challenge prevents cancer infiltration to the lung in the second challenge. This preventive effect of ECA against tumor growth in the second challenge is aided by cancer antigen-specific T cell immunity. Overall, these findings show that ECA is a nanomaterial with dual functions as a photothermal therapy for treating primary cancers and as immunotherapy for preventing recurrence and metastasis.

High Performance Gold Nanorods@DNA Self-Assembled Drug-Loading System for Cancer Thermo-Chemotherapy in the Second Near-Infrared Optical Window

In terms of synergistic cancer therapy, biological nanomaterials with a second near-infrared (NIR-II) window response can greatly increase photothermal effects and photoacoustic imaging performance. Herein, we report a novel stimuli-responsive multifunctional drug-loading system which was constructed by integrating miniature gold nanorods (GNR) as the NIR-II photothermal nanorods and cyclic ternary aptamer (CTA) composition as a carrier for chemotherapy drugs. In this system, doxorubicin hydrochloride (DOX, a chemotherapy drug) binds to the G-C base pairs of the CTA, which exhibited a controlled release behavior based on the instability of G-C base pairs in the slightly acidic tumor microenvironment. Upon the 1064 nm (NIR-II biowindow) laser irradiation, the strong photothermal and promoted cargo release properties endow gold nanorods@CTA (GNR@CTA) nanoparticles displaying excellent synergistic anti-cancer effect. Moreover, the GNR@CTA of NIR also possesses thermal imaging and photoacoustic (PA) imaging properties due to the strong NIR region absorbance. This work enables to obtaining a stimuli-responsive “all-in-one” nanocarrier, which are promising candidate for bimodal imaging diagnosis and chemo-photothermal synergistic therapy.

In Situ Growth of a Metal-Organic Framework on Graphene Oxide for the Chemo-Photothermal Therapy of Bacterial Infection in Bone Repair

Bacterial infection with high morbidity (>30%) seriously affects the defect's healing after bone transplantation. To this end, chemotherapy and photothermal therapy have been utilized for antibacterial treatment owing to their high selectivity and minimal toxicity. However, they also face several dilemmas. For example, bacterial biofilms prevented the penetration of antibacterial agents and local temperatures (over 70 °C) caused by the photothermal therapy damaged normal tissue. Herein, a co-dispersion nanosystem with chemo-photothermal function was constructed via the in situ growth of zeolitic imidazolate framework-8 (ZIF-8) on graphene oxide (GO) nanosheets. In this nanosystem, GO generates a local temperature (∼50 °C) to increase the permeability of a bacterial biofilm under near-infrared laser irradiation. Then, Zn ions released by ZIF-8 seized this chance to react with the bacterial membrane and inactivate it, thus realizing efficient sterilization in a low-temperature environment. This antibacterial system was incorporated into a poly-l-lactic acid scaffold for bone repair. Results showed that the scaffold showed a high antibacterial rate of 85% against both Escherichia coli and Staphylococcus aureus. In vitro cell tests showed that the scaffold promoted cell proliferation.

A-DA'D-A Structured Organic Phototheranostics for NIR-II Fluorescence/Photoacoustic Imaging-Guided Photothermal and Photodynamic Synergistic Therapy

Multimodal imaging-guided combinational phototherapies triggered by a single near-infrared (NIR) laser are highly desirable. However, their development is still a big challenge. Herein, we have developed an "acceptor-donor-acceptor'-donor-acceptor" structured organic phototheranostics (Y16-Pr) with strong light-harvesting ability in the NIR region. After being modified with polyethylene glycol (PEG), the obtained biocompatible nanoparticles (Y16-Pr-PEG NPs) could conduct NIR-II fluorescence imaging (FLI) and photoacoustic imaging (PAI) and perform photothermal therapy (PTT) and photodynamic therapy (PDT) simultaneously. Notably, Y16-Pr-PEG NPs showed an impressive photothermal conversion efficiency (PCE) of 82.4% under 808 nm laser irradiation. The irradiated NPs could also produce hydroxyl radicals (•OH) and singlet oxygen (¹O₂) for type I and type II PDT, respectively. In vivo and in vitro experiments revealed that the Y16-Pr-PEG NPs significantly inhibit tumor cell growth without apparent toxic side effects under laser irradiation. Overall, the single-laser-triggered multifunctional phototheranostic Y16-Pr-PEG NPs can achieve NIR-II FLI/PAI-guided synergistic PTT/PDT against tumors.

An enzyme-responsive and NIR-triggered lipid-polymer hybrid nanoplatform for synergistic photothermal/chemo cancer therapy

A combination of photothermal therapy (PTT) and chemotherapy is an emerging therapeutic strategy with promising clinical prospects in cancer treatment. Despite the huge progress achieved in the past years, a number of obstacles still hamper the therapeutic efficacy of this synergistic modality such as uneven heat distribution, lack of targetability of anti-cancer agents and dosage-related side effects. Thus, developing a nanoplatform for targeted drug delivery against cancer is of great necessity. Herein, a lipid-polymer hybrid nanosystem (LP/ID) based on polyethyleneimine (PEI)-lecithin-polyethylene glycol (PEG) was fabricated to co-load indocyanine green (ICG) and dichloroacetate (DCA) for combined photothermal/chemotherapy. DCA and ICG were linked to the PEI backbone to form a dense hydrophobic core through amide bonds and electrostatic interactions, which increased the payload of DCA and ICG as well as achieved enzyme-responsive drug release because of the overexpressed amidase in tumor cells. Lecithin and DSPE-PEG₂₀₀₀ self-assembled around the hydrophobic complexes to obtain prolonged blood circulation and attenuated systemic toxicity of the hybrid nanosystem. The prepared LP/ID exhibited favourable stability in a physiological environment, good tumor imaging properties, and satisfactory photothermal/chemotherapeutic performance. Moreover, LP/ID could also enhance the cellular uptake and tumor retention capacity in comparison with free drug administration. Notably, by co-loading two therapeutic agents with different anti-cancer mechanisms, an obvious inhibitory effect on tumor growth was observed with negligible damage to normal tissues and organs because of the synergistic photothermal/chemotherapy effect, indicating the great potential of LP/ID as a robust nanoplatform for cancer treatment.

Mitochondria-Targeted Degradable Nanocomposite Combined with Laser and Ultrasound for Synergistic Tumor Therapies

Although the development of safe and efficient cancer therapeutic agents is essential, this process remains challenging. In this study, a mitochondria-targeted degradable nanoplatform (PDA-MnO₂-IR780) for synergistic photothermal, photodynamic, and sonodynamic tumor treatment was investigated. PDA-MnO₂-IR780 exhibits superior photothermal properties owing to the integration of polydopamine, MnO₂, and IR780. IR780, a photosensitizer and sonosensitizer, was used for photodynamic therapy and sonodynamic therapy. When PDA-MnO₂-IR780 was delivered to the tumor site, MnO₂ was decomposed by hydrogen peroxide, producing Mn²⁺ and oxygen. Meanwhile, alleviating tumor hypoxia promoted the production of reactive oxygen species during photodynamic therapy and sonodynamic therapy. Moreover, large amounts of reactive oxygen species could reduce the expression of heat shock proteins and increase the heat sensitivity of tumor cells, thereby improving the photothermal treatment effect. In turn, hyperthermia caused by photothermal therapy accelerated the production of reactive oxygen species in photodynamic therapy. IR780 selectively accumulation in mitochondria also promoted tumor apoptosis. In this system, the mutual promotion of photothermal therapy and photodynamic therapy/sonodynamic therapy had an enhanced therapeutic effect. Moreover, the responsive degradable characteristic of PDA-MnO₂-IR780 in the tumor microenvironment ensured excellent biological safety. These results reveal a great potential of PDA-MnO₂-IR780 for safe and highly-efficiency synergistic therapy for cancer.

Mesoporous Doxorubicin-Loaded Polydopamine Nanoparticles Coated with a Platelet Membrane Suppress Tumor Growth in a Murine Model of Human Breast Cancer

Bringing together photothermal therapy and chemotherapy (photothermal-chemotherapy, PT-CT) is a highly promising clinical approach but requires the development of intelligent multifunctional delivery vectors. In this work, we prepared mesoporous polydopamine nanoparticles (MPDA NPs) loaded with the chemotherapeutic drug doxorubicin (DOX). These NPs were then coated with the platelet membrane (PLTM). The coated MPDA NPs are spherical and clearly mesoporous in structure. They have a particle size of approximately 184 nm and pore size of ca. 45 nm. The NPs are potent photothermal agents and efficient DOX carriers, with increased rates of drug release observed in vitro in conditions representative of the tumor microenvironment. The NPs are preferentially taken up by cancer cells but not by macrophage cells, and while cytocompatible with healthy cells are highly toxic to cancer cells. An in vivo murine model of human breast cancer revealed that the NPs can markedly slow the growth of a tumor (ca. 9-fold smaller after 14 days' treatment), have extended pharmacokinetics compared to free DOX (with DOX still detectable in the bloodstream after 24 h when the NPs are applied), and are highly targeted with minimal off-site effects on the heart, liver, spleen, kidney, and lungs.

A Narrative Review of Cell-Based Approaches for Cranial Bone Regeneration

Current cranial repair techniques combine the use of autologous bone grafts and biomaterials. In addition to their association with harvesting morbidity, autografts are often limited by insufficient quantity of bone stock. Biomaterials lead to better outcomes, but their effectiveness is often compromised by the unpredictable lack of integration and structural failure. Bone tissue engineering offers the promising alternative of generating constructs composed of instructive biomaterials including cells or cell-secreted products, which could enhance the outcome of reconstructive treatments. This review focuses on cell-based approaches with potential to regenerate calvarial bone defects, including human studies and preclinical research. Further, we discuss strategies to deliver extracellular matrix, conditioned media and extracellular vesicles derived from cell cultures. Recent advances in 3D printing and bioprinting techniques that appear to be promising for cranial reconstruction are also discussed. Finally, we review cell-based gene therapy approaches, covering both unregulated and regulated gene switches that can create spatiotemporal patterns of transgenic therapeutic molecules. In summary, this review provides an overview of the current developments in cell-based strategies with potential to enhance the surgical armamentarium for regenerating cranial vault defects.

Acidic TME-Responsive Nano-Bi2 Se3 @MnCaP as a NIR-II-Triggered Free Radical Generator for Hypoxia-Irrelevant Phototherapy with High Specificity and Immunogenicity

Here, acidic tumor microenvironment (TME)-responsive nano-Bi₂ Se₃ @MnCaP, as a near-infrared-II (NIR-II) biowindow-triggered free radical generator for hypoxia-irrelevant phototherapy, is elaborately developed by biomimetic mineralization of MnCaP onto 2, 2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (AIPH)-loaded mesoporous nano-Bi₂ Se₃ to form Bi₂ Se₃ /AIPH@MnCaP (BAM). Surface mineral of MnCaP can be degraded under mild acidity, leading to the release of both Mn²⁺ and AIPH. The leached Mn²⁺ not only facilitates chemodynamic therapy (CDT) via hydroxyl radicals (^• OH) from Mn²⁺ -mediated Fenton-like reaction but also acts as contrast agent for magnetic resonance imaging. In another aspect, the splendid photothermal conversion capacity of BAM enables a rapid hyperthermia generation under NIR-II laser irradiation for photothermal therapy (PTT). Simultaneously, the local thermal shock can induce the disintegration of AIPH to generate alkyl radicals (^• R) for thermodynamic therapy (TDT) and accelerate Fenton-like reaction rate to augment CDT efficacy. The strong synergistic effects from cooperative CDT/PTT/TDT are applied to 4T1 tumor suppression with minimal side effects. Importantly, the combination therapy can effectively trigger immunogenetic cell death and enhance antitumor immunity for systemic tumor eradication. Collectively, this proof-of-concept study demonstrates a more efficacious and safer strategy for oxygenation-independent phototherapy, which holds a good potential for clinical translation in cancer management.

Pd-Cu nanoalloy for dual stimuli-responsive chemo-photothermal therapy against pathogenic biofilm bacteria

Photothermal therapy (PTT) is a promising strategy for antimicrobial therapy. However, the application of PTT to treat bacterial infections remains a challenge as the high temperature required for bacterial elimination can partly damage healthy tissues. Selecting the appropriate treatment temperature is therefore a key factor for PTT. In this work, we designed a near-infrared/pH dual stimuli-responsive activated procedural antibacterial system based on zeolitic imidazolate framework-8 (ZIF-8), which was bottom-up synthesized and utilized to encapsulate both Pd-Cu nanoalloy (PC) and the antibiotic amoxicillin (AMO). This procedural antibacterial therapy comprises chemotherapy (CT) and PTT. The former disrupts the bacterial cell wall by releasing AMO in an acidic environment, which depends on the sensitive response of ZIF-8 to pH value change. With the progression in time, the AMO release rate decreased gradually. The latter can then significantly stimulate drug release and further complete the antibacterial effect. This impactful attack consisted of two waves that constitute the procedural therapy for bacterial infection. Accordingly, the treatment temperature required for antibacterial therapy can be significantly lowered under this mode of treatment. This antibacterial system has a significant therapeutic effect on planktonic bacteria (G⁺/G^-) and their biofilms and also has good biocompatibility; thus, it provides a promising strategy to develop an effective and safe treatment against bacterial infections. STATEMENT OF SIGNIFICANCE: We have developed a near infrared/pH dual stimuli-responsive activated procedural antibacterial system that combines enhanced antibiotic delivery with photothermal therapy and has highly efficient antimicrobial activity. The antibacterial effect of this therapy was based on two mechanisms of action: chemotherapy, in which the bacterial cell wall was first destroyed, followed by photothermal therapy. After exposure to irradiation with an 808 nm laser, the inhibition rates were 99.8% and 99.1% for Staphylococcus aureus and Pseudomonas aeruginosa, respectively, and the clearance rates for their established biofilms were 75.3% and 74.8%, respectively. Thus, this procedural antibacterial therapy has shown great potentiality for use in the photothermal therapy of bacterial infectious diseases, including biofilm elimination.

Design and Application of Near-Infrared Nanomaterial-Liposome Hybrid Nanocarriers for Cancer Photothermal Therapy

Liposomes are attractive carriers for targeted and controlled drug delivery receiving increasing attention in cancer photothermal therapy. However, the field of creating near-infrared nanomaterial-liposome hybrid nanocarriers (NIRN-Lips) is relatively little understood. The hybrid nanocarriers combine the dual superiority of nanomaterials and liposomes, with more stable particles, enhanced photoluminescence, higher tumor permeability, better tumor-targeted drug delivery, stimulus-responsive drug release, and thus exhibiting better anti-tumor efficacy. Herein, this review covers the liposomes supported various types of near-infrared nanomaterials, including gold-based nanomaterials, carbon-based nanomaterials, and semiconductor quantum dots. Specifically, the NIRN-Lips are described in terms of their feature, synthesis, and drug-release mechanism. The design considerations of NIRN-Lips are highlighted. Further, we briefly introduced the photothermal conversion mechanism of NIRNs and the cell death mechanism induced by photothermal therapy. Subsequently, we provided a brief conclusion of NIRNs-Lips applied in cancer photothermal therapy. Finally, we discussed a synopsis of associated challenges and future perspectives for the applications of NIRN-Lips in cancer photothermal therapy.

Development of Nickel Selenide@polydopamine Nanocomposites for Magnetic Resonance Imaging Guided NIR-II Photothermal Therapy

The penetration depth of near-infrared laser has greatly restricted the development of most photothermal agents. Recently, photothermal agents in the second near-infrared (NIR-II) window have drawn great attention as they can overcome above barrier. Herein, a novel "all in one" NIR-II responsive nanoplatform (nickel selenide @polydopamine nanocomposites, NiSe@PDA NCs) based on in situ coating the polydopamine (PDA) on the surface of biomineralized nickel selenide nanoparticles (NiSe NPs) for dual-model imaging-guided photothermal therapy is reported. Under the illumination of NIR-II laser (1064 nm), the photothermal conversion efficiency of NiSe@PDA NCs can reach 48.4%, which is higher than that of single NiSe NPs due to the enhanced molar extinction coefficient. In addition, because of the paramagnetic effect of NiSe NPs, the constructed NiSe@PDA NCs can be acted as T₁ contrast agent for magnetic resonance imaging (MRI). Most importantly, the MRI contrast effect is enhanced with the coating of PDA layer due to the loose structure of PDA. Ultimately, both in vitro and in vivo experiments demonstrate that the developed NCs can achieve efficient MRI-guided photothermal therapy for treating malignant tumor. Therefore, the designed NiSe@PDA NCs with excellent features show great potential for clinical MRI-guided cancer therapy.

Therapeutic Applications of Metal and Metal-Oxide Nanoparticles: Dermato-Cosmetic Perspectives

Invention of novel nanomaterials guaranteeing enhanced biomedical performance in diagnostics and therapeutics, is a perpetual initiative. In this regard, the upsurge and widespread usage of nanoparticles is a ubiquitous phenomenon, focusing predominantly on the application of submicroscopic (< 100 nm) particles. While this is facilitated attributing to their wide range of benefits, a major challenge is to create and maintain a balance, by alleviating the associated toxicity levels. In this minireview, we collate and discuss particularly recent advancements in therapeutic applications of metal and metal oxide nanoparticles in skin and cosmetic applications. On the one hand, we outline the dermatological intrusions, including applications in wound healing. On the other hand, we keep track of the recent trends in the development of cosmeceuticals via nanoparticle engrossments. The dermato-cosmetic applications of metal and metal oxide nanoparticles encompass diverse aspects, including targeted, controlled drug release, and conferring ultraviolet and antimicrobial protections to the skin. Additionally, we deliberate on the critical aspects in comprehending the advantage of rheological assessments, while characterizing the nanoparticulate systems. As an illustration, we single out psoriasis, to capture and comment on the nanodermatology-based curative standpoints. Finally, we lay a broad outlook and examine the imminent prospects.