Poly Aspartic Acid Research Articles

The Role of Process-Directing Agents on Enamel Lesion Remineralization: Fluoride Boosters.

The aim of this study was to investigate the effects of two process-directing agents (polyaspartic acid and osteopontin) used in a polymer-induced liquid-precursor (PILP) process on the remineralization of bacteria-induced enamel demineralization. Enamel demineralization lesions (depths of about 180–200 µm) were created and exposed to Streptococcus mutans, cultured with a 10% sucrose solution for 21 days, and remineralized using a PILP process (pH = 7.4, 14 days) with a calcium phosphate solution containing either polyaspartic acid or osteopontin in the presence or absence of fluoride (0.5 ppm). The specimens were examined under scanning electron microscopy. The fluoride was successfully incorporated into the PILP remineralization process for both polyaspartic acid and osteopontin. When the fluoride was added to the PILP remineralization solution, there was more uniform remineralization throughout the lesion than with either polyaspartic acid or osteopontin alone. However, in the absence of these process-directing agents, fluoride alone showed less remineralization with the formation of a predominantly surface-only layer. The PILP remineralization process relies on the ability of process-directing agents to stabilize calcium phosphate ions and holds promise for enamel lesion remineralization, and these agents, in the presence of fluoride, seem to play an important role as a booster or supplement in the continuation of remineralization by reducing the mineral gains at the surface layer.

Polyaspartic acid grafted dopamine polymer chelated Fe 3+ for magnetic resonance imaging visual photothermal therapy agent

This study aims to explore the potential of polyaspartic acid grafted dopamine copolymer (PAsp- g-DA) chelated Fe 3+ for magnetic resonance imaging (MRI) visual photothermal therapy. Polyaspartic acid grafted copolymer of covalently grafted dopamine and polyethylene glycol (PAsp- g-DA/PEG) was obtained by the ammonolysis reaction of poly succinimide (PSI), and then chelated with Fe 3+ in aqueous solution. The relaxivity in vitro, magnetic resonance imaging enhancement in vivo and photothermal conversion effect at 808 nm were investigated. The results showed that polymeric iron coordination had good near-infrared absorption and photothermal conversion properties, good magnetic resonance enhancement effect, and good longitudinal relaxation efficiency under different magnetic field intensities. In summary, this study provides a new magnetic resonance visual photothermal therapeutic agent and a new research idea for the research in related fields.

Breaking the Rebellion: Photodynamic Inactivation against Erwinia amylovora Resistant to Streptomycin.

Global crop production depends on strategies to counteract the ever-increasing spread of plant pathogens. Antibiotics are often used for large-scale treatments. As a result, Erwinia amylovora, causal agent of the contagious fire blight disease, has already evolved resistance to streptomycin (Sm). Photodynamic Inactivation (PDI) of microorganisms has been introduced as innovative method for plant protection. The aim of this study is to demonstrate that E. amylovora resistant to Sm (E. amylovora SmR) can be killed by PDI. Two photosensitizers, the synthetic B17-0024, and the natural derived anionic sodium magnesium chlorophyllin (Chl) with cell-wall-permeabilizing agents are compared in terms of their photo-killing efficiency in liquid culture with or without 100 µg/mL Sm. In vitro experiments were performed at photosensitizer concentrations of 1, 10 or 100 µM and 5 or 30 min incubation in the dark, followed by illumination at 395 nm (radiant exposure 26.6 J/cm2). The highest inactivation of seven log steps was achieved at 100 µM B17-0024 after 30 min incubation. Shorter incubation (5 min), likely to represent field conditions, reduced the photo-killing to 5 log steps. Chlorophyllin at 100 µM in combination with 1.2% polyaspartic acid (PASA) reduced the number of bacteria by 6 log steps. While PASA itself caused some light independent toxicity, an antibacterial effect (3 log reduction) was achieved only in combination with Chl, even at concentrations as low as 10 µM. Addition of 100 µg/mL Sm to media did not significantly increase the efficacy of the photodynamic treatment. This study proves principle that PDI can be used to treat plant diseases even if causative bacteria are resistant to conventional treatment. Therefore, PDI based on natural photosensitizers might represent an eco-friendly treatment strategy especially in organic farming.

Preparation of MPASP‐PAA/Fe3+ Composite Conductive Hydrogel with Physical and Chemical Double Crosslinking Structure and Its Application in Flexible Strain Sensors

AbstractConductive hydrogels show broad prospects in wearable electronic devices. However, the conductive hydrogel cross‐linked only by chemical bonds has the shortcomings of being hard and brittle, easy to break under pressure. In order to solve these problems, the MPASP‐PAA/Fe3+ composite conductive hydrogel is prepared by the method of physical and chemical double crosslinking using modified polyaspartic acid (MPASP) as the chemical crosslinking agent and FeCl3 as the physical crosslinking agent. Compared with traditional chemical crosslinking agents such as N′N‐methylene bisacrylamide, the MPASP can not only increase mechanical properties of the conductive hydrogel, but also improve the biodegradability and biocompatibility. At the same time, FeCl3 as a physical crosslinking agent can also enhance the conductivity and toughness of the conductive hydrogel. When MPASP and Fe3+ content are 2.5 wt% and 0.75 mol%, respectively, the MPASP‐PAA/Fe3+ composite conductive hydrogel exhibits high conductivity (0.12 S m−1), sensitivity (4.93), and stretchability (329%). In addition, its compressive strength is as high as 1081.39 KPa. The flexible strain sensor assembled by the MPASP‐PAA/Fe3+ composite conductive hydrogel can not only monitor human joint movements such as elbow and wrist bending, but also detect subtle vibrations such as vocalization and swallowing.

Performance Evaluation of Composite Antisalt Agents and the Antisalt Dynamics Simulation Mechanism.

The conventional ferrocyanide complex ([Fe(CN)6]4–) has been widely used as a scale inhibitor under mild conditions, but its oxidation at high temperature compromises the subsequent wastewater treatment processes. To conquer the inadequacies of Fe(CN)6]4–, aminotriacetamide (NTA) was synthesized using chloroacetic acid as an initial material and its molecular structure was characterized using FT-IR spectroscopy, H-NMR, and TGA. NTA was exploited in combination with polyaspartic acid (PASP) and sodium dodecyl benzene sulfonate (SDBS) to prepare a high-performance antisalt composite, and the scaling inhibitor performance was evaluated. The results revealed that as the concentration of the antisalt composite increased from 0.5 to 1.2 wt %, the solubility and inhibition rate increased by 95.6 and 12.33%, respectively, at 100 °C. The results from molecular simulation evidenced that the order of binding energy between a unit mass of the salt inhibitor and sodium chloride crystal increased in the following order; SDBS > NTA > PASP. The deformation strength between the salt inhibitor and sodium chloride crystal increased as follows: NTA > PASP > SDBS. In addition, the antisalt composite mainly hampered salt precipitation through strong adsorptions arising from both the nitrogen atom of NTA and oxygen atom of SDBS with the sodium atom of sodium chloride crystals, and as a result, it not only altered the crystalline form of sodium chloride but also reduced the adsorption of sodium atoms and eventually improved the salt solubility.

Polyaspartic acid, 2-acrylamido-2-Methyl propane sulfonic acid and sodium alginate based biocompatible stimuli responsive polymer gel for controlled release of GHK-Cu peptide for wound healing.

Stimuli responsive polymer based on Polyaspartic acid, 2-Acrylamido-2-methylpropane sulfonic acid and sodium alginate (NaAlg) were synthesized using two cross-linkers Ethylene glycol dimethacrylate (EGDMA) and TMPTA (Trimethylolpropane triacrylate). The polymers were standardized and optimized to obtain a polymer with maximum swelling in distilled water, saline, glucose and solutions of varying pH. The synthesized polymer swelled well in distilled water, glucose solution and acidic- alkaline medium. The biocompatibility of the polymer was evaluated for blood compatibility and protein adsorption. The polymer with maximum swelling property was used for peptide release studies. The polymer was further used to study the peptide encapsulation and release efficiency of the polymeric material which was confirmed by FTIR, Scanning Emission Microscope and EDX. The encapsulation efficiency of the polymer for encapsulating (glycyl-l-histidyl-l-lysine-copper) GHK-Cu was observed to be 55.26% and peptide release of 51.84% was observed for Ethylene glycol dimethacrylate based polymer after 24h whereas for Trimethylolpropane triacrylate based polymer the encapsulation efficiency was observed to be 49.6% and release was 39.01%. The EGDMA based polymer was further examined under in vivo studies in order to evaluate the efficiency of the synthesized polymer. The in vivo studies include wound closure, histopathological analysis, biochemical and toxicity assay. The material has shown promising results for both in vivo and in vitro studies.

Magnesium slag for remediation of cadmium‐ and arsenic‐contaminated paddy soil: A field study

AbstractThe accumulation of heavy metals like cadmium (Cd) and metalloids like arsenic (As) in plants can do harm to human health through the food chain, especially through the rice (Oryza sativa L.). To solve this problem, this study researched the application of magnesium slag (MS) and polyaspartic acid (PASP), which could accelerate rice growth and improve yield, increase soil pH and activate rice enzyme activity as well as reduce the bioavailability of Cd and As in the soil. After these two different treatments, rice yield increased by 17.0% and 18.9%, respectively. Meanwhile, the bioavailable As decreased by 49.1% and 42.5%, while the bioavailable Cd reduced by 72.6% and 44.3%. Besides, the Cd content in rice grains reduced by 77.7% and 17.3%, respectively, after two different treatments. In the MS treatment, the As content in rice grains was reduced by 21.8%, but showed no significant response to the other treatment. The contents of bioavailable Cd and As (determined by one‐step extraction) in soil were decreased by MS and PASP, which was favourable for the reduction of Cd and As accumulation in rice. The health risk assessment showed that the application of passivators can effectively reduce the risk of carcinogenesis, but it was still unacceptable. The application dose of MS and PASP still needs further exploration.

In Situ Tumor Vaccination with Calcium-Linked Degradable Coacervate Nanocomplex Co-Delivering Photosensitizer and TLR7/8 Agonist to Trigger Effective Anti-Tumor Immune Responses.

In situ anti-tumor vaccination is an attractive type of cancer immunotherapy which relies on the effectiveness of dendritic cells (DCs) to engulf tumor antigens, become activated, and present antigens to T cells in lymphoid tissue. Here, a multifunctional nanocomplex based on calcium crosslinked polyaspartic acid conjugated to either a toll-like receptor (TLR)7/8 agonist or a photosensitizer is reported. Intratumoral administration of the nanocomplex followed by laser irradiation induces cell killing and hence generation of a pool of tumor-associated antigens, with concomitant promotion of DCs maturation and expansion of T cells in tumor-draining lymph nodes. Suppression of tumor growth is observed both at the primary site and at the distal site, thereby hinting at successful induction of an adaptive anti-tumor response. This strategy holds promise for therapeutic application in a pre-operative and post-operative setting to leverage to mutanome of the patient's own tumor to mount immunological memory to clear residual tumor cells and metastasis.

Comparison of Synthetic vs. Biogenic Polymeric Process-Directing Agents for Intrafibrillar Mineralization of Collagen.

With the aging population, there is a growing need for mineralized tissue restoration and synthetic bone substitutes. Previous studies have shown that a polymer-induced liquid-precursor (PILP) process can successfully mineralize collagen substrates to achieve compositions found in native bone and dentin. This process also leads to intrafibrillar apatitic crystals with their [001] axes aligned roughly parallel to the long axis of the collagen fibril, emulating the nanostructural organization found in native bone and dentin. When demineralized bovine bone was remineralized via the PILP process using osteopontin (OPN), the samples were able to activate mouse marrow-derived osteoclasts to similar levels to those of native bone, suggesting a means for fabricating bioactive bone substitutes that could trigger remodeling through the native bone multicellular unit (BMU). In order to determine if OPN derived from bovine milk could be a cost-effective process-directing agent, the mineralization of type I collagen scaffolds using this protein was compared to the benchmark polypeptide of polyaspartic acid (sodium salt; pAsp). In this set of experiments, we found that OPN led to much faster and more uniform mineralization when compared with pAsp, making it a cheaper and commercially attractive alternative for mineralized tissue restorations.

C-Axis-Oriented Platelets of Crystalline Hydroxyapatite in Biomimetic Intrafibrillar Mineralization of Polydopamine-Functionalized Collagen Type I.

Mineralized collagen fibrils are important basic building blocks of calcified tissues, such as bone and dentin. Polydopamine (PDA) can introduce functional groups, i.e., hydroxyl and amine groups, on the surfaces of type I collagen (Col-I) as possible nucleation sites of calcium phosphate (CaP) crystallization. Molecular bindings in between PDA and Col-I fibrils (Col-PDA) have been found to significantly reduce the interfacial energy. The wetting effect, mainly hydrophilicity due to the functional groups, escalates the degree of mineralization. The assembly of Col-I molecules into fibrils was initiated at the designated number of collagenous molecules and PDA. In contrast to the infiltration of amorphous calcium phosphate (ACP) precursors into the Col-I matrix by polyaspartic acid (pAsp), this collagen assembly process allows nucleation and ACP to exist in advance by PDA in the intrafibrillar matrix. PDA bound to specific sites, i.e., gap and overlap zones, by the regular arrangement of Col-I fibrils enhanced ACP nucleation and thus mineralization. As a result, the c-axis-oriented platelets of crystalline hydroxyapatite in the Col-I fibril matrix were observed in the enhanced mineralization through PDA functionalization.

Characterization of scalants and strategies for scaling mitigation in membrane distillation of alkaline concentrated circulating cooling water

Treatment of circulating cooling water via reverse osmosis for water reuse is attractive. However, the discharge of the concentrated circulating cooling water (CCCW) is still an issue to environment. In this paper, direct contact membrane distillation (DCMD) was exploited to treat alkaline CCCW for water reclamation and volume reduction. Results suggested that the alkaline CCCW can be concentrated to achieve high volume concentration factor. DCMD performance decline was primarily due to calcium carbonate (CaCO3) scaling. The CaCO3 deposited on the membrane surface was identified as calcite. Various strategies were adopted to mitigate membrane scaling. Acidization of the CCCW can effectively improve system performance. Additionally, the main scalant transformed from CaCO3 to calcium sulfate (CaSO4) with initial pH decrease. Physical cleaning using deionized water can effectively remove CaSO4 and restore DCMD performance. Compared with commercial antiscalants (sodium polyaspartic acid and amino trimethylene phosphonic acid), EDTA showed excellent scale-inhibition performance. The calcium and magnesium in the CCCW were efficiently pre-removed by chemical softening and ion exchange methods, resulting in improvement of DCMD performance. Given scale inhibition and chemical agent costs, chemical softening was the best strategy to alleviate membrane scaling. Our work suggested that DCMD can be selected as a promising approach for treating the high alkaline CCCW combined with proper strategies to control membrane scaling.

Photodynamic Inactivation of plant pathogens part II: fungi

The constantly increasing demand for agricultural produce from organic and conventional farming calls for new, sustainable, and biocompatible solutions for crop protection. The overuse of fungicides leading to contamination of both produce and environment and the emergence of plant pathogenic fungi that are resistant to conventional treatments warrant the need for new methods to combat fungal infections in the field. We here deliver the follow-up study to our research on the Photodynamic Inactivation (PDI) of plant pathogenic bacteria (Glueck et al. in Photochem Photobiol Sci 18(7):1700–1708, 2019) by expanding the scope to fungal pathogens. Both fungal species employed in this study—Alternaria solani and Botrytis cinerea—cause substantial crop and economic losses. Sodium magnesium chlorophyllin (Chl, approved as food additive E140) in combination with Na2EDTA and the chlorin e6 derivative B17-0024 holding cationic moieties serve as eco-friendly photoactive compounds. Effectiveness of the antifungal PDI was measured by inhibition of growth of mycelial spheres (average diameter 2–3 mm) after incubation with the photosensitizer for 100 min and subsequent illumination using a LED array (395 nm, 106.6 J cm−2). One hundred micromolar Chl combined with 5 mM Na2EDTA was able to successfully photokill 94.1% of A. solani and 91.7% of B. cinerea samples. PDI based on B17-0024 can completely inactivate A. solani at 10 times lower concentration (10 µM); however, for B. cinerea, the concentration required for complete eradication was similar to that of Chl with Na2EDTA (100 µM). Using a plant compatibility assay based on Fragaria vesca, we further demonstrate that both photosensitizers neither affect host plant development nor cause significant leaf damage. The plants were sprayed with 300 µL of treatment solution used for PDI (one or three treatments on consecutive days) and plant growth was monitored for 21 days. Only minor leaf damage was observed in samples exposed to the chelators Na2EDTA and polyaspartic acid, but overall plant development was unaffected. In conclusion, our results suggest that sodium magnesium chlorophyllin in combination with EDTA and B17-0024 could serve as effective and safe photofungicides.Graphical abstract

Development of an enhanced immunoassay based on protein nanoparticles displaying an IgG-binding domain and luciferase.

Detection of small amounts of target molecules with high sensitivity is important for the diagnosis of many diseases, including cancers, and is particularly important to detect early stages of disease. Here, we report the development of a temperature-responsive fusion protein (ELP-DCN) comprised of an elastin-like polypeptide (ELP), poly-aspartic acid (D), antibody-binding domain C (C), and NanoLuc luciferase (N). ELP-DCN proteins form nanoparticles above a certain threshold temperature that display an antibody-binding domain and NanoLuc luciferase on their surface. ELP-DCN nanoparticles can be applied for enhancement of immunoassay systems because they provide more antibody-binding sites and an increased number of luciferase molecules, resulting in an increase in assay signal. Here, we report the detection of human serum albumin (HSA) as a model protein using anti-HSA and ELP-DCN proteins. Upon formation of ELP-DCN nanoparticles, the detection limit improved tenfold compared to the monomeric form of ELP-DCN.

Direct Cellular Delivery of Exogenous Genetic Material and Protein via Colloidal Nano-Assemblies with Biopolymer.

Direct cytosolic delivery of large biomolecules that bypass the endocytic pathways is a promising strategy for therapeutic applications. Recent works have shown that small-molecule, nanoparticle, and polymer-based carriers can be designed for direct cytosolic delivery. It has been shown that the specific surface chemistry of the carrier, nanoscale assembly between the carrier and cargo molecule, good colloidal stability, and low surface charge of the nano-assembly are critical for non-endocytic uptake processes. Here we report a guanidinium-terminated polyaspartic acid micelle for direct cytosolic delivery of protein and DNA. The polymer delivers the protein/DNA directly to the cytosol by forming a nano-assembly, and it is observed that <200 nm size of colloidal assembly with near-zero surface charge is critical for efficient cytosolic delivery. This work shows the importance of size and colloidal property of the nano-assembly for carrier-based cytosolic delivery of large biomolecules.

Multiple crystallization pathways of amorphous calcium carbonate in the presence of poly(aspartic acid) with a chain length of 30

Amorphous calcium carbonate transforms into crystalline calcite or vaterite with different morphologies via multiple crystallization pathways in the presence of poly(aspartic acid) with a chain length of 30 at different concentrations.

RETRACTED ARTICLE: Exosome-delivered BMP-2 and polyaspartic acid promotes tendon bone healing in rotator cuff tear via Smad/RUNX2 signaling pathway

Statement of Retraction Lei Han, Hong Liu, Huajun Fu, Yugen Hu, Weili Fang & Junsheng Liu - 2022, Exosome-delivered BMP-2 and polyaspartic acid promotes tendon bone healing in rotator cuff tear via Smad/RUNX2 signaling pathway, Bioengineered 13(1), doi: 10.1080/21655979.2021.2019871 Since publication, significant concerns have been raised about the integrity of the data and reported results in the article. When approached for an explanation, the authors did not provide their original data or any necessary supporting information. As verifying the validity of published work is core to the integrity of the scholarly record, we are therefore retracting the article. All authors listed in this publication have been informed. We have been informed in our decision-making by our editorial policies and the COPE guidelines. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.

Fabrication of Poly (Aspartic) Acid Functionalized Graphene Quantum Dots Based FRET Sensor for Selective and Sensitive Detection of MAGE-A11 Antigen

Fabrication of Poly (Aspartic) Acid Functionalized Graphene Quantum Dots Based FRET Sensor for Selective and Sensitive Detection of MAGE-A11 Antigen

Synthesis of polyaspartic acid-capped 2-aminoethylamino acid as a green water treatment agent and study of its inhibition performance and mechanism for calcium scales

Polyaspartic acid (PASP), a well-known green scale inhibitor for industrial water treatment, might be decomposed with prolonged duration, and its anti-scaling performance against CaCO3 and CaSO4 is diminished at a low concentration (<10 mg L−1) and a high temperature. With semi-ethylenediaminetetraacetic acid (EDTA) tetrasodium salt as the mimicking model, novel phosphorus-free PASP-capped 2-aminoethylamino acid (PASP–ED2A) containing side chains bearing multi-functional groups is rationally designed and successfully prepared via the ring-opening reaction of cheap poly(succinimide) under mild reaction conditions with the assistance of readily available 2-aminoethyl amino acid. The static scale inhibition method is used to evaluate the scale inhibition performance of the as-synthesized PASP derivative. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy are utilized to monitor the crystallization process of calcium carbonate and calcium sulfate scales, and density functional theory calculations are conducted to shed light on the relationship between the molecular structure and scale inhibition mechanism of PASP–ED2A. Results show that the as-prepared PASP–ED2A shows better scale inhibition performance for CaCO3 and CaSO4 than PASP with a low concentration, a high temperature, and an extended duration. Particularly, PASP–ED2A with a concentration of 10 mg L−1 exhibits the best scale inhibition performance for CaCO3; its scale inhibition capacity is about two times as much as that of PASP. The reason lies in that the coordination atoms in the molecular structure of PASP–ED2A can chelate with Ca2+ to inhibit the combination of Ca2+ with anions and prevent the generation of CaCO3 and CaSO4 scales. The PASP–ED2A derivative can more efficiently retard the formation and growth of CaCO3 and CaSO4 crystal nuclei and exerts better inhibition performance against CaCO3 and CaSO4 scales than PASP.

Effects of reducing and postponing controlled-release urea application on soil nitrogen regulation and maize grain yield

Controlled-release urea (CRU-N) fertilizer application is a solution to improve the utilization rate of nitrogen (N), reduce economic costs and improve crop yields. It is significant to study the effects of release CRU-N reduction and the combined application of conventional urea on soil N control and the large-scale maize planting system. In this study, the effects of controlled-release nitrogen fertilizer reduction and postponement on soil nitrogen components, enzyme activities, and yields were investigated. Seven treatments were set up in this study, including no N fertilizer (CK), 100% conventional urea (U), 100% controlled-release urea (S), 30% controlled-release urea (SU3/7), 50% controlled-release urea (SU5/5), 70% controlled-release urea (SU7/3) and Sodium Salt of Polyaspartic Acid (PASP)-N. The results showed that mixed CRU-N and urea increased yields and net benefits compared with conventional urea at the same application rate of N, and reduced N loss. The application of CRU-N at 70% for maize represented the best overall effects. Compared with U treatment, soil ammonium nitrogen (NH4-N), soil nitrate-nitrogen (NO3-N), and microbial biomass nitrogen (SMB-N) of CRU-N at 70% (SU7/3) increased by 35.00%, 15.53%, and 25.04%. However, soil nitrate reductase (S-NR) and urease (S-UA) were the best in SU5/5 and significantly higher than other treatments. The applications of CRU-N would effectively increase soil N; CRU-N in 50% proportion can promote the maize root growth and improve the efficient utilization of N by soil microorganisms. Like the yields (9186.61 kg/hm2), expertly in the proportion of 70% CRU-N (SU7/3) plays a vital role in a wheat-maize rotation system, which can potentially be used to improve the yields, nitrogen use efficiency, and net benefit with low N losses. In conclusion, using CRU-N fertilize effectively improves soil nitrogen, and various ratios of CRU-N can ensure the continuous release the nutrients during the growing period. And among the different proportions of CRU-N, it is optimal in SU7/3. Keywords: controlled-release urea, nitrogen regulation, maize grain yield, soil, reducing, postponing DOI: 10.25165/j.ijabe.20221501.6888 Citation: Ji P T, Peng Y J, Cui Y W, Li X L, Tao P J, Zhang Y C. Effects of reducing and postponing controlled-release urea application on soil nitrogen regulation and maize grain yield. Int J Agric & Biol Eng, 2022; 15(1): 116–123.

In situ formation of J-aggregate in the tumor microenvironment using acidity responsive polypeptide nanoparticle encapsulating galactose-conjugated BODIPY dye for NIR-II phototheranostics.

Through the activation of packing arrangements of dyes to modulate their photophysical and/or photochemical properties, not only new NIR-II dyes but tumor-specific NIR-II imaging and therapy can also be achieved. Herein, we designed an acid-responsive polypeptide nanoparticle (P-ipr@Gal) encapsulated with a pH-sensitive amphiphilic polypeptide (P-ipr) as a carrier for the galactose-conjugated BODIPY (Gal-BDP) dye. When P-ipr@Gal NPs are enriched in tumor regions by the EPR effect, the acidic microenvironment (pH 6.4-6.8) promotes the disintegration of P-ipr@Gal nanomicelles and the release of sufficient Gal-BDP. The protonation of the julolidine nitrogen of the Gal-BDP dye switched on the molecular stacking transformation from the H-aggregate to J-aggregate. The J-aggregate significantly enhanced the redshift absorption and emission intensity, which enhanced the fluorescence brightness and photothermal therapeutic effect in the tumor region. We also prepared J-aggregates PAsp@Gal with non-acidic responsive polyaspartic acid benzyl esters (PAsp) encapsulated Gal-BDP, which remained "always-on" with J-aggregate characteristics. The P-ipr@Gal (or PAsp@Gal) J-aggregate has a maximum emission peak redshifted to nearly 1064 nm, with a 3.5-fold increase in the emission intensity compared to the H-aggregate at pH 7.4. Based on the effective accumulation of tumor sites and considerable PCE (>40%), P-ipr@Gal nanoparticles have a lower background and higher tumor background ratio, which makes them a potential NIR-II imaging-guided photothermal therapy agents.