Laser-Engineered Gold Nanorod Nanocontainers for Triggered Drug Delivery and Plasmonic Sensing

PGR-P-2455

Key facts

Type of research degree: PhD
Application deadline: Wednesday 1 July 2026
Project start date: Thursday 1 October 2026
Country eligibility: International (open to all nationalities, including the UK)
Funding: Non-funded
Supervisors: Dr Kevin Critchley and Professor Stephen Evans
Schools: School of Physics and Astronomy
Research groups/institutes: Molecular and Nanoscale Physics

<h2 class="heading hide-accessible">Summary</h2>

Gold nanorods are among the most exciting nanomaterials for biomedical and analytical applications because of their strong and tuneable plasmonic absorption in the near infrared, where light penetrates biological tissue relatively effectively. In our recent work, we demonstrated a new route to reshape silica coated gold nanorods using nanosecond pulsed laser irradiation, transforming the Au core within a thin silica shell and generating well defined internal nanocavities while retaining an anisotropic plasmonic response. This laser driven process creates a new class of hybrid nanostructures that combine photothermal functionality, structural confinement, and accessible nanoscale voids, offering clear opportunities in triggered drug delivery, biosensing, and plasmon enhanced detection. This PhD project will build on that platform and develop these laser engineered AuNR silica nanostructures into functional nanocontainers for biomedical and diagnostic applications. The central idea is that the cavity created during laser reshaping can act as a confined loading site for molecular cargo or as a plasmonically active sensing volume. The project will explore how these materials can be designed, loaded, functionalised, and interrogated to create particles that not only respond to light, but also perform useful tasks such as controlled release of therapeutic molecules or optical detection of chemical and biological targets. The recent study showed that cavity formation is controllable through laser fluence and off-resonance irradiation, and that reshaping leads to strong local field enhancement within the cavity region, providing a particularly promising basis for sensing strategies such as surface-enhanced Raman scattering.

<h2 class="heading hide-accessible">Full description</h2>

The overall aim of the PhD is to develop plasmonic nanocontainers based on laser reshaped Au nanorods and establish design rules linking particle geometry, cavity formation, loading behaviour, optical response, and triggered function. The project will address questions such as: <ul data-end="3061" data-start="2537"> <li data-end="2634" data-section-id="1uw9ne7" data-start="2537"> How can laser reshaping be used to reliably generate nanocavities of defined size and geometry? </li> <li data-end="2744" data-section-id="ekxmha" data-start="2635"> Can these cavities be used to load and retain molecular cargo such as drugs, dyes, or responsive molecules? </li> <li data-end="2866" data-section-id="1vplbtt" data-start="2745"> How can the silica shell and Au surface be chemically modified for selective targeting, sensing, or controlled release? </li> <li data-end="2954" data-section-id="1ei1t6w" data-start="2867"> Can these particles act as plasmonic hotspots for highly sensitive optical detection? </li> <li data-end="3061" data-section-id="gdgwwf" data-start="2955"> How does nanoscale geometry influence photothermal response, release behaviour, and sensing performance? </li> </ul> <h2 data-end="3091" data-section-id="1p7azrt" data-start="3063">Proposed Objectives</h2> <h3 data-end="3156" data-section-id="1hy27zm" data-start="3093">1. Optimisation of Au nanorod nanocontainer fabrication</h3> The student will begin by refining the synthesis of Au nanorods and their encapsulation within thin silica shells, followed by nanosecond pulsed laser reshaping to generate controllable internal cavities. Building on our recent findings, the student will investigate how laser wavelength, fluence, pulse number, and starting nanorod geometry influence the final cavity dimensions, core morphology, optical spectra, and reproducibility. <h3 data-end="3711" data-section-id="1a0k520" data-start="3632">2. Development of nanocontainers for drug loading and triggered release</h3> A major strand of the project will focus on using the cavity and porous silica architecture as a platform for molecular loading. The student will investigate how small molecules, fluorophores, model drugs, or biologically relevant cargo can be introduced into or around the cavity region, and how surface chemistry can be tailored to control loading efficiency and retention. The project will then explore triggered release mechanisms, for example through optical stimulation, local photothermal heating, shell permeability changes, or responsive surface capping strategies. <h3 data-end="4352" data-section-id="f5cvxs" data-start="4292">3. Exploiting cavity-enhanced plasmonics for sensing</h3> Our recent modelling indicates strong field enhancement inside the newly formed cavity, suggesting clear potential for localised sensing. This part of the PhD will investigate how the cavity region can be used as a confined sensing zone for Raman active probes, analytes, or biomolecular recognition events. The student will explore how reshaped particles can be functionalised for selective sensing and assess their performance using optical spectroscopy, including extinction and Raman-based measurements. <h3 data-end="4952" data-section-id="1w4rfx7" data-start="4900">4. Structure property function relationships</h3> A core scientific goal of the PhD will be to establish relationships between nanoscale structure and application performance. The student will correlate TEM/STEM derived morphology, shell characteristics, cavity size, crystallographic changes, and optical response with functional outputs such as loading capacity, release kinetics, photothermal response, and sensing sensitivity. This will allow rational design of particles with application specific performance. <h3 data-end="5471" data-section-id="a6v0h8" data-start="5419">5. Towards biologically relevant performance</h3> Depending on progress and student interests, the later stages of the project may include evaluation of particle stability and function in more complex environments, such as buffered media, protein containing solutions, or cell relevant conditions. This could include examining how particle surface chemistry, shell porosity, and photothermal behaviour influence biological compatibility and performance. <h2 data-end="5906" data-section-id="ihn8xu" data-start="5877">Methods and Training</h2> This is an experimental nanoscience project with strong interdisciplinary links across nanomaterials synthesis, plasmonics, spectroscopy, microscopy, and biomedical nanotechnology. The student will receive training in a broad range of advanced methods, likely to include: <ul data-end="6634" data-start="6188"> <li data-end="6228" data-section-id="behd1u" data-start="6188"> colloidal synthesis of gold nanorods </li> <li data-end="6282" data-section-id="hp2zyk" data-start="6229"> silica shell growth and surface functionalisation </li> <li data-end="6341" data-section-id="6tasat" data-start="6283"> nanosecond laser processing and photothermal reshaping </li> <li data-end="6398" data-section-id="1fkdgtt" data-start="6342"> UV vis NIR spectroscopy and optical characterisation </li> <li data-end="6457" data-section-id="15mi2oi" data-start="6399"> electron microscopy, TEM/STEM and morphology analysis </li> <li data-end="6485" data-section-id="1o7fdiw" data-start="6458"> Raman/SERS measurements </li> <li data-end="6518" data-section-id="1yg2orb" data-start="6486"> drug or probe loading assays </li> <li data-end="6555" data-section-id="ku2ozo" data-start="6519"> photothermal and release studies </li> <li data-end="6634" data-section-id="t0212" data-start="6556"> data analysis and, where appropriate, electromagnetic or thermal modelling </li> </ul> The project builds on an established research platform with access to excellent facilities, including advanced spectroscopy, electron microscopy, and nanoscale characterisation tools. In the underlying study, Au nanorods were characterised using UV vis NIR spectroscopy, TEM, STEM and 4D STEM, with modelling used to understand both optical field enhancement and heat generation.The student will join a supportive supervisory environment and receive training in both experimental practice and scientific communication.

<h2 class="heading">How to apply</h2>

To apply for this project you will need to make a formal application for research degree study through the <a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University website</a>. You will need to create a login ID with a username and PIN. • For Application type please select Research Degrees, Research Postgraduate. • The admission year for this project is 2026/27 Academic Year. • You will need to select your Planned Course of Study from a drop down menu. For this project, scroll down and select PhD Physics & Astronomy Full Time. • The project start date for this project is 1 October 2026, please use this as your Proposed Start Date of Research. • Please state clearly in the research information section that the research degree you wish to be considered for is Laser-Engineered Gold Nanorod Nanocontainers for Triggered Drug Delivery and Plasmonic Sensing as well as <a href="https://eps.leeds.ac.uk/physics/staff/4104/dr-kevin-critchley">Dr Kevin Critchley</a> as your proposed supervisor. Please state clearly in the Finance Section, the funding that you are applying for, if you are self-funding or externally sponsored. More information on how to apply is available on our website <a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">here</a>. You will be required to provide a personal statement which outlines your interest in the project you are applying for, why you have chosen it and how your skills map onto the requirements of the project. Applications will be considered on an ongoing basis. Potential applicants are strongly encouraged to contact the supervisors for an informal discussion before making a formal application. We also advise that you apply at the earliest opportunity as the application and selection process may close early, should we receive a sufficient number of applications or that a suitable candidate is appointed. If you are applying for the UK Only Leeds Doctoral Scholarship or the UK Only Leeds Opportunity Research Scholarship, you must provide your documents in support of your application by the Scholarship closing date of 1 April 2026. Please note that you must provide the following documents in support of your application by the closing date of Wednesday 1 July 2026 if you are self funding or externally sponsored: <ul> <li>Full Transcripts of all degree study or if in final year of study, full transcripts to date including grading scheme</li> <li>Personal Statement outlining your interest in the project</li> <li>CV</li> </ul> If English is not your first language, you must provide evidence that you meet the University's minimum English language requirements below. As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.

<h2 class="heading heading--sm">Entry requirements</h2>

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

<h2 class="heading heading--sm">English language requirements</h2>

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.

<h2 class="heading">Funding on offer</h2>

Self-Funded or externally sponsored students are welcome to apply. Scholarship opportunities open from October 2025 UK – The <a href="https://phd.leeds.ac.uk/funding/209-leeds-doctoral-scholarships-2024">Leeds Doctoral Scholarship</a> (closing date: 1 April 2026) and <a href="https://phd.leeds.ac.uk/funding/234-leeds-opportunity-research-scholarship-2022">Leeds Opportunity Research Scholarship</a> (closing date: 1 April 2026) are available to UK applicants. <a href="https://phd.leeds.ac.uk/funding/60-alumni-bursary">Alumni Bursary</a> is available to graduates of the University of Leeds. Non-UK – The <a href="https://phd.leeds.ac.uk/funding/48-china-scholarship-council-university-of-leeds-scholarships-2026">China Scholarship Council-University of Leeds Scholarship</a> is available to nationals of China (now closed for October 2026 entry). The <a href="https://phd.leeds.ac.uk/funding/73-leeds-marshall-scholarship">Leeds Marshall Scholarship</a> is available to support US citizens. <a href="https://phd.leeds.ac.uk/funding/60-alumni-bursary">Alumni Bursary</a> is available to graduates of the University of Leeds. Please note that if you are successful in securing an academic offer for PhD study, this does not mean that you have been successful in securing an offer of funding. If you are applying for the Leeds Doctoral Scholarship, Leeds Opportunity Research Scholarship, China Scholarship Council-University of Leeds Scholarship or Leeds Marshall Scholarship, you will need to complete a separate application, specific to these scholarships, to be considered for funding. You will be responsible for paying the overtime fee in full in your writing up/overtime year (£340 in Session 2025/26), but the scholarship maintenance allowance will continue to be paid for up to 6 months in the final year of award. Important: Please note that that the award does not cover the costs associated with moving to the UK. All such costs (<a href="https://www.leeds.ac.uk/international-visas-immigration/doc/applying-student-visa">visa, Immigration Health Surcharge</a>, flights etc) would have to be met by yourself, or you will need to find an alternative funding source. Please refer to the <a href="https://www.ukcisa.org.uk/">UKCISA</a> website for information regarding Fee Status for Non-UK Nationals.

<h2 class="heading">Contact details</h2>

For further information about this project, please contact Dr Kevin Critchley by emailing <a href="mailto:EMAIL@leeds.ac.uk">k.critchley@leeds.ac.uk</a> or by calling +44 (0)113 343 3872. For further information about your application, please contact PGR Admissions by email to <a href="mailto:phd@engineering.leeds.ac.uk">phd@engineering.leeds.ac.uk</a>